diff --git a/.mockery.yaml b/.mockery.yaml
index 1fd18b8..cb5c70c 100644
--- a/.mockery.yaml
+++ b/.mockery.yaml
@@ -3,11 +3,11 @@ dir: mocks/
 outpkg: mocks
 issue-845-fix: True
 packages:
-  spend-sparrow/internal/service:
+  spend-sparrow/internal/core:
     interfaces:
       Random:
       Clock:
       Mail:
-  spend-sparrow/internal/db:
+  spend-sparrow/internal/authentication:
     interfaces:
-      Auth:
+      Db:
diff --git a/internal/account/service.go b/internal/account/service.go
index 30feb26..f0cc2e6 100644
--- a/internal/account/service.go
+++ b/internal/account/service.go
@@ -4,29 +4,31 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"github.com/google/uuid"
-	"github.com/jmoiron/sqlx"
 	"log/slog"
+	"spend-sparrow/internal/auth_types"
+	"spend-sparrow/internal/core"
 	"spend-sparrow/internal/db"
 	"spend-sparrow/internal/service"
-	"spend-sparrow/internal/types"
+
+	"github.com/google/uuid"
+	"github.com/jmoiron/sqlx"
 )
 
 type Service interface {
-	Add(ctx context.Context, user *types.User, name string) (*Account, error)
-	UpdateName(ctx context.Context, user *types.User, id string, name string) (*Account, error)
-	Get(ctx context.Context, user *types.User, id string) (*Account, error)
-	GetAll(ctx context.Context, user *types.User) ([]*Account, error)
-	Delete(ctx context.Context, user *types.User, id string) error
+	Add(ctx context.Context, user *auth_types.User, name string) (*Account, error)
+	UpdateName(ctx context.Context, user *auth_types.User, id string, name string) (*Account, error)
+	Get(ctx context.Context, user *auth_types.User, id string) (*Account, error)
+	GetAll(ctx context.Context, user *auth_types.User) ([]*Account, error)
+	Delete(ctx context.Context, user *auth_types.User, id string) error
 }
 
 type ServiceImpl struct {
 	db     *sqlx.DB
-	clock  service.Clock
-	random service.Random
+	clock  core.Clock
+	random core.Random
 }
 
-func NewServiceImpl(db *sqlx.DB, random service.Random, clock service.Clock) Service {
+func NewServiceImpl(db *sqlx.DB, random core.Random, clock core.Clock) Service {
 	return ServiceImpl{
 		db:     db,
 		clock:  clock,
@@ -34,14 +36,14 @@ func NewServiceImpl(db *sqlx.DB, random service.Random, clock service.Clock) Ser
 	}
 }
 
-func (s ServiceImpl) Add(ctx context.Context, user *types.User, name string) (*Account, error) {
+func (s ServiceImpl) Add(ctx context.Context, user *auth_types.User, name string) (*Account, error) {
 	if user == nil {
-		return nil, types.ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	newId, err := s.random.UUID(ctx)
 	if err != nil {
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	err = service.ValidateString(name, "name")
@@ -76,9 +78,9 @@ func (s ServiceImpl) Add(ctx context.Context, user *types.User, name string) (*A
 	return account, nil
 }
 
-func (s ServiceImpl) UpdateName(ctx context.Context, user *types.User, id string, name string) (*Account, error) {
+func (s ServiceImpl) UpdateName(ctx context.Context, user *auth_types.User, id string, name string) (*Account, error) {
 	if user == nil {
-		return nil, types.ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 	err := service.ValidateString(name, "name")
 	if err != nil {
@@ -87,7 +89,7 @@ func (s ServiceImpl) UpdateName(ctx context.Context, user *types.User, id string
 	uuid, err := uuid.Parse(id)
 	if err != nil {
 		slog.ErrorContext(ctx, "account update", "err", err)
-		return nil, fmt.Errorf("could not parse Id: %w", service.ErrBadRequest)
+		return nil, fmt.Errorf("could not parse Id: %w", core.ErrBadRequest)
 	}
 
 	tx, err := s.db.BeginTxx(ctx, nil)
@@ -103,10 +105,10 @@ func (s ServiceImpl) UpdateName(ctx context.Context, user *types.User, id string
 	err = tx.GetContext(ctx, &account, `SELECT * FROM account WHERE user_id = ? AND id = ?`, user.Id, uuid)
 	err = db.TransformAndLogDbError(ctx, "account Update", nil, err)
 	if err != nil {
-		if errors.Is(err, db.ErrNotFound) {
-			return nil, fmt.Errorf("account %v not found: %w", id, service.ErrBadRequest)
+		if errors.Is(err, core.ErrNotFound) {
+			return nil, fmt.Errorf("account %v not found: %w", id, core.ErrBadRequest)
 		}
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	timestamp := s.clock.Now()
@@ -136,14 +138,14 @@ func (s ServiceImpl) UpdateName(ctx context.Context, user *types.User, id string
 	return &account, nil
 }
 
-func (s ServiceImpl) Get(ctx context.Context, user *types.User, id string) (*Account, error) {
+func (s ServiceImpl) Get(ctx context.Context, user *auth_types.User, id string) (*Account, error) {
 	if user == nil {
-		return nil, service.ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 	uuid, err := uuid.Parse(id)
 	if err != nil {
 		slog.ErrorContext(ctx, "account get", "err", err)
-		return nil, fmt.Errorf("could not parse Id: %w", service.ErrBadRequest)
+		return nil, fmt.Errorf("could not parse Id: %w", core.ErrBadRequest)
 	}
 
 	var account Account
@@ -158,9 +160,9 @@ func (s ServiceImpl) Get(ctx context.Context, user *types.User, id string) (*Acc
 	return &account, nil
 }
 
-func (s ServiceImpl) GetAll(ctx context.Context, user *types.User) ([]*Account, error) {
+func (s ServiceImpl) GetAll(ctx context.Context, user *auth_types.User) ([]*Account, error) {
 	if user == nil {
-		return nil, service.ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	accounts := make([]*Account, 0)
@@ -174,14 +176,14 @@ func (s ServiceImpl) GetAll(ctx context.Context, user *types.User) ([]*Account,
 	return accounts, nil
 }
 
-func (s ServiceImpl) Delete(ctx context.Context, user *types.User, id string) error {
+func (s ServiceImpl) Delete(ctx context.Context, user *auth_types.User, id string) error {
 	if user == nil {
-		return service.ErrUnauthorized
+		return core.ErrUnauthorized
 	}
 	uuid, err := uuid.Parse(id)
 	if err != nil {
 		slog.ErrorContext(ctx, "account delete", "err", err)
-		return fmt.Errorf("could not parse Id: %w", service.ErrBadRequest)
+		return fmt.Errorf("could not parse Id: %w", core.ErrBadRequest)
 	}
 
 	tx, err := s.db.BeginTxx(ctx, nil)
@@ -200,7 +202,7 @@ func (s ServiceImpl) Delete(ctx context.Context, user *types.User, id string) er
 		return err
 	}
 	if transactionsCount > 0 {
-		return fmt.Errorf("account has transactions, cannot delete: %w", service.ErrBadRequest)
+		return fmt.Errorf("account has transactions, cannot delete: %w", core.ErrBadRequest)
 	}
 
 	res, err := tx.ExecContext(ctx, "DELETE FROM account WHERE id = ? and user_id = ?", uuid, user.Id)
diff --git a/internal/types/auth.go b/internal/auth_types/types.go
similarity index 98%
rename from internal/types/auth.go
rename to internal/auth_types/types.go
index b91e27f..fef0477 100644
--- a/internal/types/auth.go
+++ b/internal/auth_types/types.go
@@ -1,4 +1,4 @@
-package types
+package auth_types
 
 import (
 	"time"
diff --git a/internal/db/auth.go b/internal/authentication/db.go
similarity index 66%
rename from internal/db/auth.go
rename to internal/authentication/db.go
index f4eb361..7dec9ee 100644
--- a/internal/db/auth.go
+++ b/internal/authentication/db.go
@@ -1,11 +1,12 @@
-package db
+package authentication
 
 import (
 	"context"
 	"database/sql"
 	"errors"
 	"log/slog"
-	"spend-sparrow/internal/types"
+	"spend-sparrow/internal/auth_types"
+	"spend-sparrow/internal/core"
 	"strings"
 	"time"
 
@@ -13,36 +14,36 @@ import (
 	"github.com/jmoiron/sqlx"
 )
 
-type Auth interface {
-	InsertUser(ctx context.Context, user *types.User) error
-	UpdateUser(ctx context.Context, user *types.User) error
-	GetUserByEmail(ctx context.Context, email string) (*types.User, error)
-	GetUser(ctx context.Context, userId uuid.UUID) (*types.User, error)
+type Db interface {
+	InsertUser(ctx context.Context, user *auth_types.User) error
+	UpdateUser(ctx context.Context, user *auth_types.User) error
+	GetUserByEmail(ctx context.Context, email string) (*auth_types.User, error)
+	GetUser(ctx context.Context, userId uuid.UUID) (*auth_types.User, error)
 	DeleteUser(ctx context.Context, userId uuid.UUID) error
 
-	InsertToken(ctx context.Context, token *types.Token) error
-	GetToken(ctx context.Context, token string) (*types.Token, error)
-	GetTokensByUserIdAndType(ctx context.Context, userId uuid.UUID, tokenType types.TokenType) ([]*types.Token, error)
-	GetTokensBySessionIdAndType(ctx context.Context, sessionId string, tokenType types.TokenType) ([]*types.Token, error)
+	InsertToken(ctx context.Context, token *auth_types.Token) error
+	GetToken(ctx context.Context, token string) (*auth_types.Token, error)
+	GetTokensByUserIdAndType(ctx context.Context, userId uuid.UUID, tokenType auth_types.TokenType) ([]*auth_types.Token, error)
+	GetTokensBySessionIdAndType(ctx context.Context, sessionId string, tokenType auth_types.TokenType) ([]*auth_types.Token, error)
 	DeleteToken(ctx context.Context, token string) error
 
-	InsertSession(ctx context.Context, session *types.Session) error
-	GetSession(ctx context.Context, sessionId string) (*types.Session, error)
-	GetSessions(ctx context.Context, userId uuid.UUID) ([]*types.Session, error)
+	InsertSession(ctx context.Context, session *auth_types.Session) error
+	GetSession(ctx context.Context, sessionId string) (*auth_types.Session, error)
+	GetSessions(ctx context.Context, userId uuid.UUID) ([]*auth_types.Session, error)
 	DeleteSession(ctx context.Context, sessionId string) error
 	DeleteOldSessions(ctx context.Context) error
 	DeleteOldTokens(ctx context.Context) error
 }
 
-type AuthSqlite struct {
+type DbSqlite struct {
 	db *sqlx.DB
 }
 
-func NewAuthSqlite(db *sqlx.DB) *AuthSqlite {
-	return &AuthSqlite{db: db}
+func NewDbSqlite(db *sqlx.DB) *DbSqlite {
+	return &DbSqlite{db: db}
 }
 
-func (db AuthSqlite) InsertUser(ctx context.Context, user *types.User) error {
+func (db DbSqlite) InsertUser(ctx context.Context, user *auth_types.User) error {
 	_, err := db.db.ExecContext(ctx, `
 		INSERT INTO user (user_id, email, email_verified, email_verified_at, is_admin, password, salt, created_at) 
 		VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
@@ -50,17 +51,17 @@ func (db AuthSqlite) InsertUser(ctx context.Context, user *types.User) error {
 
 	if err != nil {
 		if strings.Contains(err.Error(), "email") {
-			return ErrAlreadyExists
+			return core.ErrAlreadyExists
 		}
 
 		slog.ErrorContext(ctx, "SQL error InsertUser", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	return nil
 }
 
-func (db AuthSqlite) UpdateUser(ctx context.Context, user *types.User) error {
+func (db DbSqlite) UpdateUser(ctx context.Context, user *auth_types.User) error {
 	_, err := db.db.ExecContext(ctx, `
 		UPDATE user 
 		SET email_verified = ?, email_verified_at = ?, password = ?
@@ -69,13 +70,13 @@ func (db AuthSqlite) UpdateUser(ctx context.Context, user *types.User) error {
 
 	if err != nil {
 		slog.ErrorContext(ctx, "SQL error UpdateUser", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	return nil
 }
 
-func (db AuthSqlite) GetUserByEmail(ctx context.Context, email string) (*types.User, error) {
+func (db DbSqlite) GetUserByEmail(ctx context.Context, email string) (*auth_types.User, error) {
 	var (
 		userId          uuid.UUID
 		emailVerified   bool
@@ -92,17 +93,17 @@ func (db AuthSqlite) GetUserByEmail(ctx context.Context, email string) (*types.U
 		WHERE email = ?`, email).Scan(&userId, &emailVerified, &emailVerifiedAt, &password, &salt, &createdAt)
 	if err != nil {
 		if errors.Is(err, sql.ErrNoRows) {
-			return nil, ErrNotFound
+			return nil, core.ErrNotFound
 		} else {
 			slog.ErrorContext(ctx, "SQL error GetUser", "err", err)
-			return nil, types.ErrInternal
+			return nil, core.ErrInternal
 		}
 	}
 
-	return types.NewUser(userId, email, emailVerified, emailVerifiedAt, isAdmin, password, salt, createdAt), nil
+	return auth_types.NewUser(userId, email, emailVerified, emailVerifiedAt, isAdmin, password, salt, createdAt), nil
 }
 
-func (db AuthSqlite) GetUser(ctx context.Context, userId uuid.UUID) (*types.User, error) {
+func (db DbSqlite) GetUser(ctx context.Context, userId uuid.UUID) (*auth_types.User, error) {
 	var (
 		email           string
 		emailVerified   bool
@@ -119,92 +120,92 @@ func (db AuthSqlite) GetUser(ctx context.Context, userId uuid.UUID) (*types.User
 		WHERE user_id = ?`, userId).Scan(&email, &emailVerified, &emailVerifiedAt, &password, &salt, &createdAt)
 	if err != nil {
 		if errors.Is(err, sql.ErrNoRows) {
-			return nil, ErrNotFound
+			return nil, core.ErrNotFound
 		} else {
 			slog.ErrorContext(ctx, "SQL error GetUser", "err", err)
-			return nil, types.ErrInternal
+			return nil, core.ErrInternal
 		}
 	}
 
-	return types.NewUser(userId, email, emailVerified, emailVerifiedAt, isAdmin, password, salt, createdAt), nil
+	return auth_types.NewUser(userId, email, emailVerified, emailVerifiedAt, isAdmin, password, salt, createdAt), nil
 }
 
-func (db AuthSqlite) DeleteUser(ctx context.Context, userId uuid.UUID) error {
+func (db DbSqlite) DeleteUser(ctx context.Context, userId uuid.UUID) error {
 	tx, err := db.db.BeginTx(ctx, nil)
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not start transaction", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	_, err = tx.ExecContext(ctx, "DELETE FROM account WHERE user_id = ?", userId)
 	if err != nil {
 		_ = tx.Rollback()
 		slog.ErrorContext(ctx, "Could not delete accounts", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	_, err = tx.ExecContext(ctx, "DELETE FROM token WHERE user_id = ?", userId)
 	if err != nil {
 		_ = tx.Rollback()
 		slog.ErrorContext(ctx, "Could not delete user tokens", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	_, err = tx.ExecContext(ctx, "DELETE FROM session WHERE user_id = ?", userId)
 	if err != nil {
 		_ = tx.Rollback()
 		slog.ErrorContext(ctx, "Could not delete sessions", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	_, err = tx.ExecContext(ctx, "DELETE FROM user WHERE user_id = ?", userId)
 	if err != nil {
 		_ = tx.Rollback()
 		slog.ErrorContext(ctx, "Could not delete user", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	_, err = tx.ExecContext(ctx, "DELETE FROM treasure_chest WHERE user_id = ?", userId)
 	if err != nil {
 		_ = tx.Rollback()
 		slog.ErrorContext(ctx, "Could not delete user", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	_, err = tx.ExecContext(ctx, "DELETE FROM \"transaction\" WHERE user_id = ?", userId)
 	if err != nil {
 		_ = tx.Rollback()
 		slog.ErrorContext(ctx, "Could not delete user", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	err = tx.Commit()
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not commit transaction", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	return nil
 }
 
-func (db AuthSqlite) InsertToken(ctx context.Context, token *types.Token) error {
+func (db DbSqlite) InsertToken(ctx context.Context, token *auth_types.Token) error {
 	_, err := db.db.ExecContext(ctx, `
 		INSERT INTO token (user_id, session_id, type, token, created_at, expires_at)
 		VALUES (?, ?, ?, ?, ?, ?)`, token.UserId, token.SessionId, token.Type, token.Token, token.CreatedAt, token.ExpiresAt)
 
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not insert token", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	return nil
 }
 
-func (db AuthSqlite) GetToken(ctx context.Context, token string) (*types.Token, error) {
+func (db DbSqlite) GetToken(ctx context.Context, token string) (*auth_types.Token, error) {
 	var (
 		userId       uuid.UUID
 		sessionId    string
-		tokenType    types.TokenType
+		tokenType    auth_types.TokenType
 		createdAtStr string
 		expiresAtStr string
 		createdAt    time.Time
@@ -219,29 +220,29 @@ func (db AuthSqlite) GetToken(ctx context.Context, token string) (*types.Token,
 	if err != nil {
 		if errors.Is(err, sql.ErrNoRows) {
 			slog.InfoContext(ctx, "Token not found", "token", token)
-			return nil, ErrNotFound
+			return nil, core.ErrNotFound
 		} else {
 			slog.ErrorContext(ctx, "Could not get token", "err", err)
-			return nil, types.ErrInternal
+			return nil, core.ErrInternal
 		}
 	}
 
 	createdAt, err = time.Parse(time.RFC3339, createdAtStr)
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not parse token.created_at", "err", err)
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	expiresAt, err = time.Parse(time.RFC3339, expiresAtStr)
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not parse token.expires_at", "err", err)
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
-	return types.NewToken(userId, sessionId, token, tokenType, createdAt, expiresAt), nil
+	return auth_types.NewToken(userId, sessionId, token, tokenType, createdAt, expiresAt), nil
 }
 
-func (db AuthSqlite) GetTokensByUserIdAndType(ctx context.Context, userId uuid.UUID, tokenType types.TokenType) ([]*types.Token, error) {
+func (db DbSqlite) GetTokensByUserIdAndType(ctx context.Context, userId uuid.UUID, tokenType auth_types.TokenType) ([]*auth_types.Token, error) {
 	query, err := db.db.QueryContext(ctx, `
 		SELECT token, created_at, expires_at 
 		FROM token 
@@ -250,13 +251,13 @@ func (db AuthSqlite) GetTokensByUserIdAndType(ctx context.Context, userId uuid.U
 
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not get token", "err", err)
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	return getTokensFromQuery(ctx, query, userId, "", tokenType)
 }
 
-func (db AuthSqlite) GetTokensBySessionIdAndType(ctx context.Context, sessionId string, tokenType types.TokenType) ([]*types.Token, error) {
+func (db DbSqlite) GetTokensBySessionIdAndType(ctx context.Context, sessionId string, tokenType auth_types.TokenType) ([]*auth_types.Token, error) {
 	query, err := db.db.QueryContext(ctx, `
 		SELECT token, created_at, expires_at 
 		FROM token 
@@ -265,14 +266,14 @@ func (db AuthSqlite) GetTokensBySessionIdAndType(ctx context.Context, sessionId
 
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not get token", "err", err)
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	return getTokensFromQuery(ctx, query, uuid.Nil, sessionId, tokenType)
 }
 
-func getTokensFromQuery(ctx context.Context, query *sql.Rows, userId uuid.UUID, sessionId string, tokenType types.TokenType) ([]*types.Token, error) {
-	var tokens []*types.Token
+func getTokensFromQuery(ctx context.Context, query *sql.Rows, userId uuid.UUID, sessionId string, tokenType auth_types.TokenType) ([]*auth_types.Token, error) {
+	var tokens []*auth_types.Token
 
 	hasRows := false
 	for query.Next() {
@@ -289,54 +290,54 @@ func getTokensFromQuery(ctx context.Context, query *sql.Rows, userId uuid.UUID,
 		err := query.Scan(&token, &createdAtStr, &expiresAtStr)
 		if err != nil {
 			slog.ErrorContext(ctx, "Could not scan token", "err", err)
-			return nil, types.ErrInternal
+			return nil, core.ErrInternal
 		}
 
 		createdAt, err = time.Parse(time.RFC3339, createdAtStr)
 		if err != nil {
 			slog.ErrorContext(ctx, "Could not parse token.created_at", "err", err)
-			return nil, types.ErrInternal
+			return nil, core.ErrInternal
 		}
 
 		expiresAt, err = time.Parse(time.RFC3339, expiresAtStr)
 		if err != nil {
 			slog.ErrorContext(ctx, "Could not parse token.expires_at", "err", err)
-			return nil, types.ErrInternal
+			return nil, core.ErrInternal
 		}
 
-		tokens = append(tokens, types.NewToken(userId, sessionId, token, tokenType, createdAt, expiresAt))
+		tokens = append(tokens, auth_types.NewToken(userId, sessionId, token, tokenType, createdAt, expiresAt))
 	}
 
 	if !hasRows {
-		return nil, ErrNotFound
+		return nil, core.ErrNotFound
 	}
 
 	return tokens, nil
 }
 
-func (db AuthSqlite) DeleteToken(ctx context.Context, token string) error {
+func (db DbSqlite) DeleteToken(ctx context.Context, token string) error {
 	_, err := db.db.ExecContext(ctx, "DELETE FROM token WHERE token = ?", token)
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not delete token", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 	return nil
 }
 
-func (db AuthSqlite) InsertSession(ctx context.Context, session *types.Session) error {
+func (db DbSqlite) InsertSession(ctx context.Context, session *auth_types.Session) error {
 	_, err := db.db.ExecContext(ctx, `
 		INSERT INTO session (session_id, user_id, created_at, expires_at) 
 		VALUES (?, ?, ?, ?)`, session.Id, session.UserId, session.CreatedAt, session.ExpiresAt)
 
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not insert new session", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	return nil
 }
 
-func (db AuthSqlite) GetSession(ctx context.Context, sessionId string) (*types.Session, error) {
+func (db DbSqlite) GetSession(ctx context.Context, sessionId string) (*auth_types.Session, error) {
 	var (
 		userId    uuid.UUID
 		createdAt time.Time
@@ -350,56 +351,56 @@ func (db AuthSqlite) GetSession(ctx context.Context, sessionId string) (*types.S
 
 	if err != nil {
 		slog.WarnContext(ctx, "Session not found", "session-id", sessionId, "err", err)
-		return nil, ErrNotFound
+		return nil, core.ErrNotFound
 	}
 
-	return types.NewSession(sessionId, userId, createdAt, expiresAt), nil
+	return auth_types.NewSession(sessionId, userId, createdAt, expiresAt), nil
 }
 
-func (db AuthSqlite) GetSessions(ctx context.Context, userId uuid.UUID) ([]*types.Session, error) {
-	var sessions []*types.Session
+func (db DbSqlite) GetSessions(ctx context.Context, userId uuid.UUID) ([]*auth_types.Session, error) {
+	var sessions []*auth_types.Session
 	err := db.db.SelectContext(ctx, &sessions, `
 			SELECT *
 			FROM session 
 			WHERE user_id = ?`, userId)
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not get sessions", "err", err)
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	return sessions, nil
 }
 
-func (db AuthSqlite) DeleteSession(ctx context.Context, sessionId string) error {
+func (db DbSqlite) DeleteSession(ctx context.Context, sessionId string) error {
 	if sessionId != "" {
 		_, err := db.db.ExecContext(ctx, "DELETE FROM session WHERE session_id = ?", sessionId)
 		if err != nil {
 			slog.ErrorContext(ctx, "Could not delete session", "err", err)
-			return types.ErrInternal
+			return core.ErrInternal
 		}
 	}
 
 	return nil
 }
 
-func (db AuthSqlite) DeleteOldSessions(ctx context.Context) error {
+func (db DbSqlite) DeleteOldSessions(ctx context.Context) error {
 	_, err := db.db.ExecContext(ctx, `
 		DELETE FROM session 
 		WHERE expires_at < datetime('now')`)
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not delete old sessions", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 	return nil
 }
 
-func (db AuthSqlite) DeleteOldTokens(ctx context.Context) error {
+func (db DbSqlite) DeleteOldTokens(ctx context.Context) error {
 	_, err := db.db.ExecContext(ctx, `
 		DELETE FROM token 
 		WHERE expires_at < datetime('now')`)
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not delete old tokens", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 	return nil
 }
diff --git a/internal/handler/auth.go b/internal/authentication/handler.go
similarity index 81%
rename from internal/handler/auth.go
rename to internal/authentication/handler.go
index 7370b98..6cf32f6 100644
--- a/internal/handler/auth.go
+++ b/internal/authentication/handler.go
@@ -1,36 +1,34 @@
-package handler
+package authentication
 
 import (
 	"errors"
 	"log/slog"
 	"net/http"
 	"net/url"
+	"spend-sparrow/internal/auth_types"
+	"spend-sparrow/internal/authentication/template"
 	"spend-sparrow/internal/core"
-	"spend-sparrow/internal/handler/middleware"
-	"spend-sparrow/internal/service"
-	"spend-sparrow/internal/template/auth"
-	"spend-sparrow/internal/types"
 	"spend-sparrow/internal/utils"
 	"time"
 )
 
-type Auth interface {
+type Handler interface {
 	Handle(router *http.ServeMux)
 }
 
-type AuthImpl struct {
-	service service.Auth
+type HandlerImpl struct {
+	service Service
 	render  *core.Render
 }
 
-func NewAuth(service service.Auth, render *core.Render) Auth {
-	return AuthImpl{
+func NewHandler(service Service, render *core.Render) Handler {
+	return HandlerImpl{
 		service: service,
 		render:  render,
 	}
 }
 
-func (handler AuthImpl) Handle(router *http.ServeMux) {
+func (handler HandlerImpl) Handle(router *http.ServeMux) {
 	router.Handle("GET /auth/signin", handler.handleSignInPage())
 	router.Handle("POST /api/auth/signin", handler.handleSignIn())
 
@@ -57,7 +55,7 @@ var (
 	securityWaitDuration = 250 * time.Millisecond
 )
 
-func (handler AuthImpl) handleSignInPage() http.HandlerFunc {
+func (handler HandlerImpl) handleSignInPage() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -71,17 +69,17 @@ func (handler AuthImpl) handleSignInPage() http.HandlerFunc {
 			return
 		}
 
-		comp := auth.SignInOrUpComp(true)
+		comp := template.SignInOrUpComp(true)
 
 		handler.render.RenderLayout(r, w, comp, nil)
 	}
 }
 
-func (handler AuthImpl) handleSignIn() http.HandlerFunc {
+func (handler HandlerImpl) handleSignIn() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
-		user, err := utils.WaitMinimumTime(securityWaitDuration, func() (*types.User, error) {
+		user, err := utils.WaitMinimumTime(securityWaitDuration, func() (*auth_types.User, error) {
 			session := core.GetSession(r)
 			email := r.FormValue("email")
 			password := r.FormValue("password")
@@ -91,14 +89,14 @@ func (handler AuthImpl) handleSignIn() http.HandlerFunc {
 				return nil, err
 			}
 
-			cookie := middleware.CreateSessionCookie(session.Id)
+			cookie := core.CreateSessionCookie(session.Id)
 			http.SetCookie(w, &cookie)
 
 			return user, nil
 		})
 
 		if err != nil {
-			if errors.Is(err, service.ErrInvalidCredentials) {
+			if errors.Is(err, ErrInvalidCredentials) {
 				utils.TriggerToastWithStatus(r.Context(), w, r, "error", "Invalid email or password", http.StatusUnauthorized)
 			} else {
 				utils.TriggerToastWithStatus(r.Context(), w, r, "error", "An error occurred", http.StatusInternalServerError)
@@ -114,7 +112,7 @@ func (handler AuthImpl) handleSignIn() http.HandlerFunc {
 	}
 }
 
-func (handler AuthImpl) handleSignUpPage() http.HandlerFunc {
+func (handler HandlerImpl) handleSignUpPage() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -129,12 +127,12 @@ func (handler AuthImpl) handleSignUpPage() http.HandlerFunc {
 			return
 		}
 
-		signUpComp := auth.SignInOrUpComp(false)
+		signUpComp := template.SignInOrUpComp(false)
 		handler.render.RenderLayout(r, w, signUpComp, nil)
 	}
 }
 
-func (handler AuthImpl) handleSignUpVerifyPage() http.HandlerFunc {
+func (handler HandlerImpl) handleSignUpVerifyPage() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -149,12 +147,12 @@ func (handler AuthImpl) handleSignUpVerifyPage() http.HandlerFunc {
 			return
 		}
 
-		signIn := auth.VerifyComp()
+		signIn := template.VerifyComp()
 		handler.render.RenderLayout(r, w, signIn, user)
 	}
 }
 
-func (handler AuthImpl) handleVerifyResendComp() http.HandlerFunc {
+func (handler HandlerImpl) handleVerifyResendComp() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -173,7 +171,7 @@ func (handler AuthImpl) handleVerifyResendComp() http.HandlerFunc {
 	}
 }
 
-func (handler AuthImpl) handleSignUpVerifyResponsePage() http.HandlerFunc {
+func (handler HandlerImpl) handleSignUpVerifyResponsePage() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -182,7 +180,7 @@ func (handler AuthImpl) handleSignUpVerifyResponsePage() http.HandlerFunc {
 		err := handler.service.VerifyUserEmail(r.Context(), token)
 
 		isVerified := err == nil
-		comp := auth.VerifyResponseComp(isVerified)
+		comp := template.VerifyResponseComp(isVerified)
 
 		var status int
 		if isVerified {
@@ -195,7 +193,7 @@ func (handler AuthImpl) handleSignUpVerifyResponsePage() http.HandlerFunc {
 	}
 }
 
-func (handler AuthImpl) handleSignUp() http.HandlerFunc {
+func (handler HandlerImpl) handleSignUp() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -216,14 +214,14 @@ func (handler AuthImpl) handleSignUp() http.HandlerFunc {
 
 		if err != nil {
 			switch {
-			case errors.Is(err, types.ErrInternal):
+			case errors.Is(err, core.ErrInternal):
 				utils.TriggerToastWithStatus(r.Context(), w, r, "error", "An error occurred", http.StatusInternalServerError)
 				return
-			case errors.Is(err, service.ErrInvalidEmail):
+			case errors.Is(err, ErrInvalidEmail):
 				utils.TriggerToastWithStatus(r.Context(), w, r, "error", "The email provided is invalid", http.StatusBadRequest)
 				return
-			case errors.Is(err, service.ErrInvalidPassword):
-				utils.TriggerToastWithStatus(r.Context(), w, r, "error", service.ErrInvalidPassword.Error(), http.StatusBadRequest)
+			case errors.Is(err, ErrInvalidPassword):
+				utils.TriggerToastWithStatus(r.Context(), w, r, "error", ErrInvalidPassword.Error(), http.StatusBadRequest)
 				return
 			}
 			// If err is "service.ErrAccountExists", then just continue
@@ -233,7 +231,7 @@ func (handler AuthImpl) handleSignUp() http.HandlerFunc {
 	}
 }
 
-func (handler AuthImpl) handleSignOut() http.HandlerFunc {
+func (handler HandlerImpl) handleSignOut() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -262,7 +260,7 @@ func (handler AuthImpl) handleSignOut() http.HandlerFunc {
 	}
 }
 
-func (handler AuthImpl) handleDeleteAccountPage() http.HandlerFunc {
+func (handler HandlerImpl) handleDeleteAccountPage() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -272,12 +270,12 @@ func (handler AuthImpl) handleDeleteAccountPage() http.HandlerFunc {
 			return
 		}
 
-		comp := auth.DeleteAccountComp()
+		comp := template.DeleteAccountComp()
 		handler.render.RenderLayout(r, w, comp, user)
 	}
 }
 
-func (handler AuthImpl) handleDeleteAccountComp() http.HandlerFunc {
+func (handler HandlerImpl) handleDeleteAccountComp() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -291,7 +289,7 @@ func (handler AuthImpl) handleDeleteAccountComp() http.HandlerFunc {
 
 		err := handler.service.DeleteAccount(r.Context(), user, password)
 		if err != nil {
-			if errors.Is(err, service.ErrInvalidCredentials) {
+			if errors.Is(err, ErrInvalidCredentials) {
 				utils.TriggerToastWithStatus(r.Context(), w, r, "error", "Password not correct", http.StatusBadRequest)
 			} else {
 				utils.TriggerToastWithStatus(r.Context(), w, r, "error", "Internal Server Error", http.StatusInternalServerError)
@@ -303,7 +301,7 @@ func (handler AuthImpl) handleDeleteAccountComp() http.HandlerFunc {
 	}
 }
 
-func (handler AuthImpl) handleChangePasswordPage() http.HandlerFunc {
+func (handler HandlerImpl) handleChangePasswordPage() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -316,12 +314,12 @@ func (handler AuthImpl) handleChangePasswordPage() http.HandlerFunc {
 			return
 		}
 
-		comp := auth.ChangePasswordComp(isPasswordReset)
+		comp := template.ChangePasswordComp(isPasswordReset)
 		handler.render.RenderLayout(r, w, comp, user)
 	}
 }
 
-func (handler AuthImpl) handleChangePasswordComp() http.HandlerFunc {
+func (handler HandlerImpl) handleChangePasswordComp() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -345,7 +343,7 @@ func (handler AuthImpl) handleChangePasswordComp() http.HandlerFunc {
 	}
 }
 
-func (handler AuthImpl) handleForgotPasswordPage() http.HandlerFunc {
+func (handler HandlerImpl) handleForgotPasswordPage() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -355,12 +353,12 @@ func (handler AuthImpl) handleForgotPasswordPage() http.HandlerFunc {
 			return
 		}
 
-		comp := auth.ResetPasswordComp()
+		comp := template.ResetPasswordComp()
 		handler.render.RenderLayout(r, w, comp, user)
 	}
 }
 
-func (handler AuthImpl) handleForgotPasswordComp() http.HandlerFunc {
+func (handler HandlerImpl) handleForgotPasswordComp() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
@@ -383,7 +381,7 @@ func (handler AuthImpl) handleForgotPasswordComp() http.HandlerFunc {
 	}
 }
 
-func (handler AuthImpl) handleForgotPasswordResponseComp() http.HandlerFunc {
+func (handler HandlerImpl) handleForgotPasswordResponseComp() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		core.UpdateSpan(r)
 
diff --git a/internal/service/auth.go b/internal/authentication/service.go
similarity index 65%
rename from internal/service/auth.go
rename to internal/authentication/service.go
index 06e782a..64424fd 100644
--- a/internal/service/auth.go
+++ b/internal/authentication/service.go
@@ -1,4 +1,4 @@
-package service
+package authentication
 
 import (
 	"context"
@@ -6,7 +6,8 @@ import (
 	"errors"
 	"log/slog"
 	"net/mail"
-	"spend-sparrow/internal/db"
+	"spend-sparrow/internal/auth_types"
+	"spend-sparrow/internal/core"
 	mailTemplate "spend-sparrow/internal/template/mail"
 	"spend-sparrow/internal/types"
 	"strings"
@@ -25,39 +26,39 @@ var (
 	ErrTokenInvalid       = errors.New("token is invalid")
 )
 
-type Auth interface {
-	SignUp(ctx context.Context, email string, password string) (*types.User, error)
+type Service interface {
+	SignUp(ctx context.Context, email string, password string) (*auth_types.User, error)
 	SendVerificationMail(ctx context.Context, userId uuid.UUID, email string)
 	VerifyUserEmail(ctx context.Context, token string) error
 
-	SignIn(ctx context.Context, session *types.Session, email string, password string) (*types.Session, *types.User, error)
-	SignInSession(ctx context.Context, sessionId string) (*types.Session, *types.User, error)
-	SignInAnonymous(ctx context.Context) (*types.Session, error)
+	SignIn(ctx context.Context, session *auth_types.Session, email string, password string) (*auth_types.Session, *auth_types.User, error)
+	SignInSession(ctx context.Context, sessionId string) (*auth_types.Session, *auth_types.User, error)
+	SignInAnonymous(ctx context.Context) (*auth_types.Session, error)
 	SignOut(ctx context.Context, sessionId string) error
 
-	DeleteAccount(ctx context.Context, user *types.User, currPass string) error
+	DeleteAccount(ctx context.Context, user *auth_types.User, currPass string) error
 
-	ChangePassword(ctx context.Context, user *types.User, sessionId string, currPass, newPass string) error
+	ChangePassword(ctx context.Context, user *auth_types.User, sessionId string, currPass, newPass string) error
 
 	SendForgotPasswordMail(ctx context.Context, email string) error
 	ForgotPassword(ctx context.Context, token string, newPass string) error
 
 	IsCsrfTokenValid(ctx context.Context, tokenStr string, sessionId string) bool
-	GetCsrfToken(ctx context.Context, session *types.Session) (string, error)
+	GetCsrfToken(ctx context.Context, session *auth_types.Session) (string, error)
 
 	CleanupSessionsAndTokens(ctx context.Context) error
 }
 
-type AuthImpl struct {
-	db             db.Auth
-	random         Random
-	clock          Clock
-	mail           Mail
+type ServiceImpl struct {
+	db             Db
+	random         core.Random
+	clock          core.Clock
+	mail           core.Mail
 	serverSettings *types.Settings
 }
 
-func NewAuth(db db.Auth, random Random, clock Clock, mail Mail, serverSettings *types.Settings) *AuthImpl {
-	return &AuthImpl{
+func NewService(db Db, random core.Random, clock core.Clock, mail core.Mail, serverSettings *types.Settings) *ServiceImpl {
+	return &ServiceImpl{
 		db:             db,
 		random:         random,
 		clock:          clock,
@@ -66,13 +67,13 @@ func NewAuth(db db.Auth, random Random, clock Clock, mail Mail, serverSettings *
 	}
 }
 
-func (service AuthImpl) SignIn(ctx context.Context, session *types.Session, email string, password string) (*types.Session, *types.User, error) {
+func (service ServiceImpl) SignIn(ctx context.Context, session *auth_types.Session, email string, password string) (*auth_types.Session, *auth_types.User, error) {
 	user, err := service.db.GetUserByEmail(ctx, email)
 	if err != nil {
-		if errors.Is(err, db.ErrNotFound) {
+		if errors.Is(err, core.ErrNotFound) {
 			return nil, nil, ErrInvalidCredentials
 		} else {
-			return nil, nil, types.ErrInternal
+			return nil, nil, core.ErrInternal
 		}
 	}
 
@@ -84,36 +85,36 @@ func (service AuthImpl) SignIn(ctx context.Context, session *types.Session, emai
 
 	newSession, err := service.createSession(ctx, user.Id)
 	if err != nil {
-		return nil, nil, types.ErrInternal
+		return nil, nil, core.ErrInternal
 	}
 
 	err = service.db.DeleteSession(ctx, session.Id)
 	if err != nil {
-		return nil, nil, types.ErrInternal
+		return nil, nil, core.ErrInternal
 	}
 
-	tokens, err := service.db.GetTokensBySessionIdAndType(ctx, session.Id, types.TokenTypeCsrf)
+	tokens, err := service.db.GetTokensBySessionIdAndType(ctx, session.Id, auth_types.TokenTypeCsrf)
 	if err != nil {
-		return nil, nil, types.ErrInternal
+		return nil, nil, core.ErrInternal
 	}
 	for _, token := range tokens {
 		err = service.db.DeleteToken(ctx, token.Token)
 		if err != nil {
-			return nil, nil, types.ErrInternal
+			return nil, nil, core.ErrInternal
 		}
 	}
 
 	return newSession, user, nil
 }
 
-func (service AuthImpl) SignInSession(ctx context.Context, sessionId string) (*types.Session, *types.User, error) {
+func (service ServiceImpl) SignInSession(ctx context.Context, sessionId string) (*auth_types.Session, *auth_types.User, error) {
 	if sessionId == "" {
 		return nil, nil, ErrSessionIdInvalid
 	}
 
 	session, err := service.db.GetSession(ctx, sessionId)
 	if err != nil {
-		return nil, nil, types.ErrInternal
+		return nil, nil, core.ErrInternal
 	}
 	if session.ExpiresAt.Before(service.clock.Now()) {
 		_ = service.db.DeleteSession(ctx, sessionId)
@@ -126,16 +127,16 @@ func (service AuthImpl) SignInSession(ctx context.Context, sessionId string) (*t
 
 	user, err := service.db.GetUser(ctx, session.UserId)
 	if err != nil {
-		return nil, nil, types.ErrInternal
+		return nil, nil, core.ErrInternal
 	}
 
 	return session, user, nil
 }
 
-func (service AuthImpl) SignInAnonymous(ctx context.Context) (*types.Session, error) {
+func (service ServiceImpl) SignInAnonymous(ctx context.Context) (*auth_types.Session, error) {
 	session, err := service.createSession(ctx, uuid.Nil)
 	if err != nil {
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	slog.InfoContext(ctx, "anonymous session created", "session-id", session.Id)
@@ -143,7 +144,7 @@ func (service AuthImpl) SignInAnonymous(ctx context.Context) (*types.Session, er
 	return session, nil
 }
 
-func (service AuthImpl) SignUp(ctx context.Context, email string, password string) (*types.User, error) {
+func (service ServiceImpl) SignUp(ctx context.Context, email string, password string) (*auth_types.User, error) {
 	_, err := mail.ParseAddress(email)
 	if err != nil {
 		return nil, ErrInvalidEmail
@@ -155,37 +156,37 @@ func (service AuthImpl) SignUp(ctx context.Context, email string, password strin
 
 	userId, err := service.random.UUID(ctx)
 	if err != nil {
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	salt, err := service.random.Bytes(ctx, 16)
 	if err != nil {
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	hash := GetHashPassword(password, salt)
 
-	user := types.NewUser(userId, email, false, nil, false, hash, salt, service.clock.Now())
+	user := auth_types.NewUser(userId, email, false, nil, false, hash, salt, service.clock.Now())
 
 	err = service.db.InsertUser(ctx, user)
 	if err != nil {
-		if errors.Is(err, db.ErrAlreadyExists) {
+		if errors.Is(err, core.ErrAlreadyExists) {
 			return nil, ErrAccountExists
 		} else {
-			return nil, types.ErrInternal
+			return nil, core.ErrInternal
 		}
 	}
 
 	return user, nil
 }
 
-func (service AuthImpl) SendVerificationMail(ctx context.Context, userId uuid.UUID, email string) {
-	tokens, err := service.db.GetTokensByUserIdAndType(ctx, userId, types.TokenTypeEmailVerify)
-	if err != nil && !errors.Is(err, db.ErrNotFound) {
+func (service ServiceImpl) SendVerificationMail(ctx context.Context, userId uuid.UUID, email string) {
+	tokens, err := service.db.GetTokensByUserIdAndType(ctx, userId, auth_types.TokenTypeEmailVerify)
+	if err != nil && !errors.Is(err, core.ErrNotFound) {
 		return
 	}
 
-	var token *types.Token
+	var token *auth_types.Token
 
 	if len(tokens) > 0 {
 		token = tokens[0]
@@ -197,11 +198,11 @@ func (service AuthImpl) SendVerificationMail(ctx context.Context, userId uuid.UU
 			return
 		}
 
-		token = types.NewToken(
+		token = auth_types.NewToken(
 			userId,
 			"",
 			newTokenStr,
-			types.TokenTypeEmailVerify,
+			auth_types.TokenTypeEmailVerify,
 			service.clock.Now(),
 			service.clock.Now().Add(24*time.Hour))
 
@@ -221,29 +222,29 @@ func (service AuthImpl) SendVerificationMail(ctx context.Context, userId uuid.UU
 	service.mail.SendMail(ctx, email, "Welcome to spend-sparrow", w.String())
 }
 
-func (service AuthImpl) VerifyUserEmail(ctx context.Context, tokenStr string) error {
+func (service ServiceImpl) VerifyUserEmail(ctx context.Context, tokenStr string) error {
 	if tokenStr == "" {
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	token, err := service.db.GetToken(ctx, tokenStr)
 	if err != nil {
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	user, err := service.db.GetUser(ctx, token.UserId)
 	if err != nil {
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
-	if token.Type != types.TokenTypeEmailVerify {
-		return types.ErrInternal
+	if token.Type != auth_types.TokenTypeEmailVerify {
+		return core.ErrInternal
 	}
 
 	now := service.clock.Now()
 
 	if token.ExpiresAt.Before(now) {
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	user.EmailVerified = true
@@ -251,21 +252,21 @@ func (service AuthImpl) VerifyUserEmail(ctx context.Context, tokenStr string) er
 
 	err = service.db.UpdateUser(ctx, user)
 	if err != nil {
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	_ = service.db.DeleteToken(ctx, token.Token)
 	return nil
 }
 
-func (service AuthImpl) SignOut(ctx context.Context, sessionId string) error {
+func (service ServiceImpl) SignOut(ctx context.Context, sessionId string) error {
 	return service.db.DeleteSession(ctx, sessionId)
 }
 
-func (service AuthImpl) DeleteAccount(ctx context.Context, user *types.User, currPass string) error {
+func (service ServiceImpl) DeleteAccount(ctx context.Context, user *auth_types.User, currPass string) error {
 	userDb, err := service.db.GetUser(ctx, user.Id)
 	if err != nil {
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	currHash := GetHashPassword(currPass, userDb.Salt)
@@ -283,7 +284,7 @@ func (service AuthImpl) DeleteAccount(ctx context.Context, user *types.User, cur
 	return nil
 }
 
-func (service AuthImpl) ChangePassword(ctx context.Context, user *types.User, sessionId string, currPass, newPass string) error {
+func (service ServiceImpl) ChangePassword(ctx context.Context, user *auth_types.User, sessionId string, currPass, newPass string) error {
 	if !isPasswordValid(newPass) {
 		return ErrInvalidPassword
 	}
@@ -308,13 +309,13 @@ func (service AuthImpl) ChangePassword(ctx context.Context, user *types.User, se
 
 	sessions, err := service.db.GetSessions(ctx, user.Id)
 	if err != nil {
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 	for _, s := range sessions {
 		if s.Id != sessionId {
 			err = service.db.DeleteSession(ctx, s.Id)
 			if err != nil {
-				return types.ErrInternal
+				return core.ErrInternal
 			}
 		}
 	}
@@ -322,7 +323,7 @@ func (service AuthImpl) ChangePassword(ctx context.Context, user *types.User, se
 	return nil
 }
 
-func (service AuthImpl) SendForgotPasswordMail(ctx context.Context, email string) error {
+func (service ServiceImpl) SendForgotPasswordMail(ctx context.Context, email string) error {
 	tokenStr, err := service.random.String(ctx, 32)
 	if err != nil {
 		return err
@@ -330,38 +331,38 @@ func (service AuthImpl) SendForgotPasswordMail(ctx context.Context, email string
 
 	user, err := service.db.GetUserByEmail(ctx, email)
 	if err != nil {
-		if errors.Is(err, db.ErrNotFound) {
+		if errors.Is(err, core.ErrNotFound) {
 			return nil
 		} else {
-			return types.ErrInternal
+			return core.ErrInternal
 		}
 	}
 
-	token := types.NewToken(
+	token := auth_types.NewToken(
 		user.Id,
 		"",
 		tokenStr,
-		types.TokenTypePasswordReset,
+		auth_types.TokenTypePasswordReset,
 		service.clock.Now(),
 		service.clock.Now().Add(15*time.Minute))
 
 	err = service.db.InsertToken(ctx, token)
 	if err != nil {
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	var mail strings.Builder
 	err = mailTemplate.ResetPassword(service.serverSettings.BaseUrl, token.Token).Render(context.Background(), &mail)
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not render reset password email", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 	service.mail.SendMail(ctx, email, "Reset Password", mail.String())
 
 	return nil
 }
 
-func (service AuthImpl) ForgotPassword(ctx context.Context, tokenStr string, newPass string) error {
+func (service ServiceImpl) ForgotPassword(ctx context.Context, tokenStr string, newPass string) error {
 	if !isPasswordValid(newPass) {
 		return ErrInvalidPassword
 	}
@@ -376,7 +377,7 @@ func (service AuthImpl) ForgotPassword(ctx context.Context, tokenStr string, new
 		return err
 	}
 
-	if token.Type != types.TokenTypePasswordReset ||
+	if token.Type != auth_types.TokenTypePasswordReset ||
 		token.ExpiresAt.Before(service.clock.Now()) {
 		return ErrTokenInvalid
 	}
@@ -384,7 +385,7 @@ func (service AuthImpl) ForgotPassword(ctx context.Context, tokenStr string, new
 	user, err := service.db.GetUser(ctx, token.UserId)
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not get user from token", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	passHash := GetHashPassword(newPass, user.Salt)
@@ -397,26 +398,26 @@ func (service AuthImpl) ForgotPassword(ctx context.Context, tokenStr string, new
 
 	sessions, err := service.db.GetSessions(ctx, user.Id)
 	if err != nil {
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	for _, session := range sessions {
 		err = service.db.DeleteSession(ctx, session.Id)
 		if err != nil {
-			return types.ErrInternal
+			return core.ErrInternal
 		}
 	}
 
 	return nil
 }
 
-func (service AuthImpl) IsCsrfTokenValid(ctx context.Context, tokenStr string, sessionId string) bool {
+func (service ServiceImpl) IsCsrfTokenValid(ctx context.Context, tokenStr string, sessionId string) bool {
 	token, err := service.db.GetToken(ctx, tokenStr)
 	if err != nil {
 		return false
 	}
 
-	if token.Type != types.TokenTypeCsrf ||
+	if token.Type != auth_types.TokenTypeCsrf ||
 		token.SessionId != sessionId ||
 		token.ExpiresAt.Before(service.clock.Now()) {
 		return false
@@ -425,12 +426,12 @@ func (service AuthImpl) IsCsrfTokenValid(ctx context.Context, tokenStr string, s
 	return true
 }
 
-func (service AuthImpl) GetCsrfToken(ctx context.Context, session *types.Session) (string, error) {
+func (service ServiceImpl) GetCsrfToken(ctx context.Context, session *auth_types.Session) (string, error) {
 	if session == nil {
-		return "", types.ErrInternal
+		return "", core.ErrInternal
 	}
 
-	tokens, _ := service.db.GetTokensBySessionIdAndType(ctx, session.Id, types.TokenTypeCsrf)
+	tokens, _ := service.db.GetTokensBySessionIdAndType(ctx, session.Id, auth_types.TokenTypeCsrf)
 
 	if len(tokens) > 0 {
 		return tokens[0].Token, nil
@@ -438,19 +439,19 @@ func (service AuthImpl) GetCsrfToken(ctx context.Context, session *types.Session
 
 	tokenStr, err := service.random.String(ctx, 32)
 	if err != nil {
-		return "", types.ErrInternal
+		return "", core.ErrInternal
 	}
 
-	token := types.NewToken(
+	token := auth_types.NewToken(
 		session.UserId,
 		session.Id,
 		tokenStr,
-		types.TokenTypeCsrf,
+		auth_types.TokenTypeCsrf,
 		service.clock.Now(),
 		service.clock.Now().Add(8*time.Hour))
 	err = service.db.InsertToken(ctx, token)
 	if err != nil {
-		return "", types.ErrInternal
+		return "", core.ErrInternal
 	}
 
 	slog.InfoContext(ctx, "CSRF-Token created", "token", tokenStr)
@@ -458,34 +459,34 @@ func (service AuthImpl) GetCsrfToken(ctx context.Context, session *types.Session
 	return tokenStr, nil
 }
 
-func (service AuthImpl) CleanupSessionsAndTokens(ctx context.Context) error {
+func (service ServiceImpl) CleanupSessionsAndTokens(ctx context.Context) error {
 	err := service.db.DeleteOldSessions(ctx)
 	if err != nil {
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	err = service.db.DeleteOldTokens(ctx)
 	if err != nil {
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	return nil
 }
 
-func (service AuthImpl) createSession(ctx context.Context, userId uuid.UUID) (*types.Session, error) {
+func (service ServiceImpl) createSession(ctx context.Context, userId uuid.UUID) (*auth_types.Session, error) {
 	sessionId, err := service.random.String(ctx, 32)
 	if err != nil {
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	createAt := service.clock.Now()
 	expiresAt := createAt.Add(24 * time.Hour)
 
-	session := types.NewSession(sessionId, userId, createAt, expiresAt)
+	session := auth_types.NewSession(sessionId, userId, createAt, expiresAt)
 
 	err = service.db.InsertSession(ctx, session)
 	if err != nil {
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	return session, nil
diff --git a/internal/template/auth/change_password.templ b/internal/authentication/template/change_password.templ
similarity index 98%
rename from internal/template/auth/change_password.templ
rename to internal/authentication/template/change_password.templ
index 9e761fb..db3351d 100644
--- a/internal/template/auth/change_password.templ
+++ b/internal/authentication/template/change_password.templ
@@ -1,4 +1,4 @@
-package auth
+package template
 
 templ ChangePasswordComp(isPasswordReset bool) {
 	<form
diff --git a/internal/authentication/template/default.go b/internal/authentication/template/default.go
new file mode 100644
index 0000000..38cdfe4
--- /dev/null
+++ b/internal/authentication/template/default.go
@@ -0,0 +1 @@
+package template
diff --git a/internal/template/auth/delete_account.templ b/internal/authentication/template/delete_account.templ
similarity index 97%
rename from internal/template/auth/delete_account.templ
rename to internal/authentication/template/delete_account.templ
index 384bace..9dd6a03 100644
--- a/internal/template/auth/delete_account.templ
+++ b/internal/authentication/template/delete_account.templ
@@ -1,4 +1,4 @@
-package auth
+package template
 
 templ DeleteAccountComp() {
 	<form
diff --git a/internal/template/auth/reset_password.templ b/internal/authentication/template/reset_password.templ
similarity index 97%
rename from internal/template/auth/reset_password.templ
rename to internal/authentication/template/reset_password.templ
index 9f45550..abdaa83 100644
--- a/internal/template/auth/reset_password.templ
+++ b/internal/authentication/template/reset_password.templ
@@ -1,4 +1,4 @@
-package auth
+package template
 
 templ ResetPasswordComp() {
 	<form
diff --git a/internal/template/auth/sign_in_or_up.templ b/internal/authentication/template/sign_in_or_up.templ
similarity index 94%
rename from internal/template/auth/sign_in_or_up.templ
rename to internal/authentication/template/sign_in_or_up.templ
index ad39b68..4e3e199 100644
--- a/internal/template/auth/sign_in_or_up.templ
+++ b/internal/authentication/template/sign_in_or_up.templ
@@ -1,13 +1,13 @@
-package auth
+package template
 
 templ SignInOrUpComp(isSignIn bool) {
 	{{
-var postUrl string
-if isSignIn {
-	postUrl = "/api/auth/signin"
-} else {
-	postUrl = "/api/auth/signup"
-}
+		var postUrl string
+		if isSignIn {
+			postUrl = "/api/auth/signin"
+		} else {
+			postUrl = "/api/auth/signup"
+		}
 	}}
 	<form
 		class="max-w-xl px-2 mx-auto flex flex-col gap-4 h-full justify-center"
diff --git a/internal/template/auth/verify.templ b/internal/authentication/template/verify.templ
similarity index 97%
rename from internal/template/auth/verify.templ
rename to internal/authentication/template/verify.templ
index 3197415..572c7b3 100644
--- a/internal/template/auth/verify.templ
+++ b/internal/authentication/template/verify.templ
@@ -1,4 +1,4 @@
-package auth
+package template
 
 templ VerifyComp() {
 	<main class="h-full">
diff --git a/internal/template/auth/verify_response.templ b/internal/authentication/template/verify_response.templ
similarity index 97%
rename from internal/template/auth/verify_response.templ
rename to internal/authentication/template/verify_response.templ
index 1b96e55..0a112f4 100644
--- a/internal/template/auth/verify_response.templ
+++ b/internal/authentication/template/verify_response.templ
@@ -1,4 +1,4 @@
-package auth
+package template
 
 templ VerifyResponseComp(isVerified bool) {
 	<main>
diff --git a/internal/core/auth.go b/internal/core/auth.go
index f51574d..151e9aa 100644
--- a/internal/core/auth.go
+++ b/internal/core/auth.go
@@ -2,7 +2,7 @@ package core
 
 import (
 	"net/http"
-	"spend-sparrow/internal/types"
+	"spend-sparrow/internal/auth_types"
 )
 
 type ContextKey string
@@ -10,13 +10,13 @@ type ContextKey string
 var SessionKey ContextKey = "session"
 var UserKey ContextKey = "user"
 
-func GetUser(r *http.Request) *types.User {
+func GetUser(r *http.Request) *auth_types.User {
 	obj := r.Context().Value(UserKey)
 	if obj == nil {
 		return nil
 	}
 
-	user, ok := obj.(*types.User)
+	user, ok := obj.(*auth_types.User)
 	if !ok {
 		return nil
 	}
@@ -24,16 +24,28 @@ func GetUser(r *http.Request) *types.User {
 	return user
 }
 
-func GetSession(r *http.Request) *types.Session {
+func GetSession(r *http.Request) *auth_types.Session {
 	obj := r.Context().Value(SessionKey)
 	if obj == nil {
 		return nil
 	}
 
-	session, ok := obj.(*types.Session)
+	session, ok := obj.(*auth_types.Session)
 	if !ok {
 		return nil
 	}
 
 	return session
 }
+
+func CreateSessionCookie(sessionId string) http.Cookie {
+	return http.Cookie{
+		Name:     "id",
+		Value:    sessionId,
+		MaxAge:   60 * 60 * 8, // 8 hours
+		Secure:   true,
+		HttpOnly: true,
+		SameSite: http.SameSiteStrictMode,
+		Path:     "/",
+	}
+}
diff --git a/internal/service/clock.go b/internal/core/clock.go
similarity index 92%
rename from internal/service/clock.go
rename to internal/core/clock.go
index 8944dc7..4e4ea67 100644
--- a/internal/service/clock.go
+++ b/internal/core/clock.go
@@ -1,4 +1,4 @@
-package service
+package core
 
 import "time"
 
diff --git a/internal/core/default.go b/internal/core/default.go
index 5b8a1ab..2830102 100644
--- a/internal/core/default.go
+++ b/internal/core/default.go
@@ -3,8 +3,6 @@ package core
 import (
 	"errors"
 	"net/http"
-	"spend-sparrow/internal/db"
-	"spend-sparrow/internal/service"
 	"spend-sparrow/internal/utils"
 	"strings"
 
@@ -14,13 +12,13 @@ import (
 
 func HandleError(w http.ResponseWriter, r *http.Request, err error) {
 	switch {
-	case errors.Is(err, service.ErrUnauthorized):
+	case errors.Is(err, ErrUnauthorized):
 		utils.TriggerToastWithStatus(r.Context(), w, r, "error", "You are not autorized to perform this operation.", http.StatusUnauthorized)
 		return
-	case errors.Is(err, service.ErrBadRequest):
+	case errors.Is(err, ErrBadRequest):
 		utils.TriggerToastWithStatus(r.Context(), w, r, "error", extractErrorMessage(err), http.StatusBadRequest)
 		return
-	case errors.Is(err, db.ErrNotFound):
+	case errors.Is(err, ErrNotFound):
 		utils.TriggerToastWithStatus(r.Context(), w, r, "error", extractErrorMessage(err), http.StatusNotFound)
 		return
 	}
diff --git a/internal/core/error.go b/internal/core/error.go
new file mode 100644
index 0000000..854e3ae
--- /dev/null
+++ b/internal/core/error.go
@@ -0,0 +1,13 @@
+package core
+
+import "errors"
+
+var (
+	ErrNotFound      = errors.New("the value does not exist")
+	ErrAlreadyExists = errors.New("row already exists")
+
+	ErrInternal     = errors.New("internal server error")
+	ErrUnauthorized = errors.New("you are not authorized to perform this action")
+
+	ErrBadRequest = errors.New("bad request")
+)
diff --git a/internal/service/mail.go b/internal/core/mail.go
similarity index 98%
rename from internal/service/mail.go
rename to internal/core/mail.go
index 9a0edd7..9bed681 100644
--- a/internal/service/mail.go
+++ b/internal/core/mail.go
@@ -1,4 +1,4 @@
-package service
+package core
 
 import (
 	"context"
diff --git a/internal/service/random_generator.go b/internal/core/random_generator.go
similarity index 87%
rename from internal/service/random_generator.go
rename to internal/core/random_generator.go
index 331afdc..143912f 100644
--- a/internal/service/random_generator.go
+++ b/internal/core/random_generator.go
@@ -1,11 +1,10 @@
-package service
+package core
 
 import (
 	"context"
 	"crypto/rand"
 	"encoding/base64"
 	"log/slog"
-	"spend-sparrow/internal/types"
 
 	"github.com/google/uuid"
 )
@@ -28,7 +27,7 @@ func (r *RandomImpl) Bytes(ctx context.Context, tsize int) ([]byte, error) {
 	_, err := rand.Read(b)
 	if err != nil {
 		slog.ErrorContext(ctx, "Error generating random bytes", "err", err)
-		return []byte{}, types.ErrInternal
+		return []byte{}, ErrInternal
 	}
 
 	return b, nil
@@ -38,7 +37,7 @@ func (r *RandomImpl) String(ctx context.Context, size int) (string, error) {
 	bytes, err := r.Bytes(ctx, size)
 	if err != nil {
 		slog.ErrorContext(ctx, "Error generating random string", "err", err)
-		return "", types.ErrInternal
+		return "", ErrInternal
 	}
 
 	return base64.StdEncoding.EncodeToString(bytes), nil
@@ -48,7 +47,7 @@ func (r *RandomImpl) UUID(ctx context.Context) (uuid.UUID, error) {
 	id, err := uuid.NewRandom()
 	if err != nil {
 		slog.ErrorContext(ctx, "Error generating random UUID", "err", err)
-		return uuid.Nil, types.ErrInternal
+		return uuid.Nil, ErrInternal
 	}
 
 	return id, nil
diff --git a/internal/core/render.go b/internal/core/render.go
index a380a49..5fab9f2 100644
--- a/internal/core/render.go
+++ b/internal/core/render.go
@@ -1,10 +1,11 @@
 package core
 
 import (
-	"github.com/a-h/templ"
 	"log/slog"
 	"net/http"
-	"spend-sparrow/internal/types"
+	"spend-sparrow/internal/auth_types"
+
+	"github.com/a-h/templ"
 )
 
 type Render struct {
@@ -28,18 +29,18 @@ func (render *Render) Render(r *http.Request, w http.ResponseWriter, comp templ.
 	render.RenderWithStatus(r, w, comp, http.StatusOK)
 }
 
-func (render *Render) RenderLayout(r *http.Request, w http.ResponseWriter, slot templ.Component, user *types.User) {
+func (render *Render) RenderLayout(r *http.Request, w http.ResponseWriter, slot templ.Component, user *auth_types.User) {
 	render.RenderLayoutWithStatus(r, w, slot, user, http.StatusOK)
 }
 
-func (render *Render) RenderLayoutWithStatus(r *http.Request, w http.ResponseWriter, slot templ.Component, user *types.User, status int) {
+func (render *Render) RenderLayoutWithStatus(r *http.Request, w http.ResponseWriter, slot templ.Component, user *auth_types.User, status int) {
 	userComp := render.getUserComp(user)
 	layout := Layout(slot, userComp, user != nil, r.URL.Path)
 
 	render.RenderWithStatus(r, w, layout, status)
 }
 
-func (render *Render) getUserComp(user *types.User) templ.Component {
+func (render *Render) getUserComp(user *auth_types.User) templ.Component {
 	if user != nil {
 		return UserComp(user.Email)
 	} else {
diff --git a/internal/db/error.go b/internal/db/error.go
index f81fe7e..3bc2a0d 100644
--- a/internal/db/error.go
+++ b/internal/db/error.go
@@ -5,33 +5,28 @@ import (
 	"database/sql"
 	"errors"
 	"log/slog"
-	"spend-sparrow/internal/types"
-)
-
-var (
-	ErrNotFound      = errors.New("the value does not exist")
-	ErrAlreadyExists = errors.New("row already exists")
+	"spend-sparrow/internal/core"
 )
 
 func TransformAndLogDbError(ctx context.Context, module string, r sql.Result, err error) error {
 	if err != nil {
 		if errors.Is(err, sql.ErrNoRows) {
-			return ErrNotFound
+			return core.ErrNotFound
 		}
 		slog.ErrorContext(ctx, "database sql", "module", module, "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	if r != nil {
 		rows, err := r.RowsAffected()
 		if err != nil {
 			slog.ErrorContext(ctx, "database rows affected", "module", module, "err", err)
-			return types.ErrInternal
+			return core.ErrInternal
 		}
 
 		if rows == 0 {
 			slog.InfoContext(ctx, "row not found", "module", module)
-			return ErrNotFound
+			return core.ErrNotFound
 		}
 	}
 
diff --git a/internal/db/migration.go b/internal/db/migration.go
index 76ed2d9..3040b93 100644
--- a/internal/db/migration.go
+++ b/internal/db/migration.go
@@ -4,7 +4,7 @@ import (
 	"context"
 	"errors"
 	"log/slog"
-	"spend-sparrow/internal/types"
+	"spend-sparrow/internal/core"
 
 	"github.com/golang-migrate/migrate/v4"
 	"github.com/golang-migrate/migrate/v4/database/sqlite3"
@@ -25,7 +25,7 @@ func RunMigrations(ctx context.Context, db *sqlx.DB, pathPrefix string) error {
 	driver, err := sqlite3.WithInstance(db.DB, &sqlite3.Config{})
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not create Migration instance", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	m, err := migrate.NewWithDatabaseInstance(
@@ -34,14 +34,14 @@ func RunMigrations(ctx context.Context, db *sqlx.DB, pathPrefix string) error {
 		driver)
 	if err != nil {
 		slog.ErrorContext(ctx, "Could not create migrations instance", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	m.Log = migrationLogger{}
 
 	if err = m.Up(); err != nil && !errors.Is(err, migrate.ErrNoChange) {
 		slog.ErrorContext(ctx, "Could not run migrations", "err", err)
-		return types.ErrInternal
+		return core.ErrInternal
 	}
 
 	return nil
diff --git a/internal/default.go b/internal/default.go
index 277c75d..4cd63d1 100644
--- a/internal/default.go
+++ b/internal/default.go
@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"os/signal"
 	"spend-sparrow/internal/account"
+	"spend-sparrow/internal/authentication"
 	"spend-sparrow/internal/core"
 	"spend-sparrow/internal/db"
 	"spend-sparrow/internal/handler"
@@ -107,13 +108,13 @@ func shutdownServer(ctx context.Context, s *http.Server, wg *sync.WaitGroup) {
 func createHandlerWithServices(ctx context.Context, d *sqlx.DB, serverSettings *types.Settings) http.Handler {
 	var router = http.NewServeMux()
 
-	authDb := db.NewAuthSqlite(d)
+	authDb := authentication.NewDbSqlite(d)
 
-	randomService := service.NewRandom()
-	clockService := service.NewClock()
-	mailService := service.NewMail(serverSettings)
+	randomService := core.NewRandom()
+	clockService := core.NewClock()
+	mailService := core.NewMail(serverSettings)
 
-	authService := service.NewAuth(authDb, randomService, clockService, mailService, serverSettings)
+	authService := authentication.NewService(authDb, randomService, clockService, mailService, serverSettings)
 	accountService := account.NewServiceImpl(d, randomService, clockService)
 	treasureChestService := service.NewTreasureChest(d, randomService, clockService)
 	transactionService := service.NewTransaction(d, randomService, clockService)
@@ -123,7 +124,7 @@ func createHandlerWithServices(ctx context.Context, d *sqlx.DB, serverSettings *
 	render := core.NewRender()
 	indexHandler := handler.NewIndex(render, clockService)
 	dashboardHandler := handler.NewDashboard(render, dashboardService, treasureChestService)
-	authHandler := handler.NewAuth(authService, render)
+	authHandler := authentication.NewHandler(authService, render)
 	accountHandler := account.NewHandler(accountService, render)
 	treasureChestHandler := handler.NewTreasureChest(treasureChestService, transactionRecurringService, render)
 	transactionHandler := handler.NewTransaction(transactionService, accountService, treasureChestService, render)
@@ -157,7 +158,7 @@ func createHandlerWithServices(ctx context.Context, d *sqlx.DB, serverSettings *
 	return wrapper
 }
 
-func dailyTaskTimer(ctx context.Context, transactionRecurring service.TransactionRecurring, auth service.Auth) {
+func dailyTaskTimer(ctx context.Context, transactionRecurring service.TransactionRecurring, auth authentication.Service) {
 	runDailyTasks(ctx, transactionRecurring, auth)
 	ticker := time.NewTicker(24 * time.Hour)
 	defer ticker.Stop()
@@ -172,7 +173,7 @@ func dailyTaskTimer(ctx context.Context, transactionRecurring service.Transactio
 	}
 }
 
-func runDailyTasks(ctx context.Context, transactionRecurring service.TransactionRecurring, auth service.Auth) {
+func runDailyTasks(ctx context.Context, transactionRecurring service.TransactionRecurring, auth authentication.Service) {
 	slog.InfoContext(ctx, "Running daily tasks")
 	_ = transactionRecurring.GenerateTransactions(ctx)
 	_ = auth.CleanupSessionsAndTokens(ctx)
diff --git a/internal/handler/dashboard.go b/internal/handler/dashboard.go
index 8bc4525..1e14b7b 100644
--- a/internal/handler/dashboard.go
+++ b/internal/handler/dashboard.go
@@ -193,7 +193,7 @@ func (handler DashboardImpl) handleDashboardTreasureChest() http.HandlerFunc {
 		if treasureChestStr != "" {
 			id, err := uuid.Parse(treasureChestStr)
 			if err != nil {
-				core.HandleError(w, r, fmt.Errorf("could not parse treasure chest: %w", service.ErrBadRequest))
+				core.HandleError(w, r, fmt.Errorf("could not parse treasure chest: %w", core.ErrBadRequest))
 				return
 			}
 
diff --git a/internal/handler/middleware/authenticate.go b/internal/handler/middleware/authenticate.go
index d20a0b7..4ba51d9 100644
--- a/internal/handler/middleware/authenticate.go
+++ b/internal/handler/middleware/authenticate.go
@@ -3,12 +3,12 @@ package middleware
 import (
 	"context"
 	"net/http"
+	"spend-sparrow/internal/authentication"
 	"spend-sparrow/internal/core"
-	"spend-sparrow/internal/service"
 	"strings"
 )
 
-func Authenticate(service service.Auth) func(http.Handler) http.Handler {
+func Authenticate(service authentication.Service) func(http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			ctx := r.Context()
@@ -31,7 +31,7 @@ func Authenticate(service service.Auth) func(http.Handler) http.Handler {
 					return
 				}
 
-				cookie := CreateSessionCookie(session.Id)
+				cookie := core.CreateSessionCookie(session.Id)
 				http.SetCookie(w, &cookie)
 			}
 
diff --git a/internal/handler/middleware/cross_site_request_forgery.go b/internal/handler/middleware/cross_site_request_forgery.go
index 4601b56..407ab2c 100644
--- a/internal/handler/middleware/cross_site_request_forgery.go
+++ b/internal/handler/middleware/cross_site_request_forgery.go
@@ -3,8 +3,8 @@ package middleware
 import (
 	"log/slog"
 	"net/http"
+	"spend-sparrow/internal/authentication"
 	"spend-sparrow/internal/core"
-	"spend-sparrow/internal/service"
 	"spend-sparrow/internal/utils"
 	"strings"
 )
@@ -31,7 +31,7 @@ func (rr *csrfResponseWriter) Write(data []byte) (int, error) {
 	return rr.ResponseWriter.Write([]byte(dataStr))
 }
 
-func CrossSiteRequestForgery(auth service.Auth) func(http.Handler) http.Handler {
+func CrossSiteRequestForgery(auth authentication.Service) func(http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			ctx := r.Context()
diff --git a/internal/handler/middleware/default.go b/internal/handler/middleware/default.go
index 0146fb5..c870d7c 100644
--- a/internal/handler/middleware/default.go
+++ b/internal/handler/middleware/default.go
@@ -1,15 +1 @@
 package middleware
-
-import "net/http"
-
-func CreateSessionCookie(sessionId string) http.Cookie {
-	return http.Cookie{
-		Name:     "id",
-		Value:    sessionId,
-		MaxAge:   60 * 60 * 8, // 8 hours
-		Secure:   true,
-		HttpOnly: true,
-		SameSite: http.SameSiteStrictMode,
-		Path:     "/",
-	}
-}
diff --git a/internal/handler/root_and_404.go b/internal/handler/root_and_404.go
index 19ad051..e09b6e4 100644
--- a/internal/handler/root_and_404.go
+++ b/internal/handler/root_and_404.go
@@ -3,7 +3,6 @@ package handler
 import (
 	"net/http"
 	"spend-sparrow/internal/core"
-	"spend-sparrow/internal/service"
 	"spend-sparrow/internal/template"
 	"spend-sparrow/internal/utils"
 
@@ -16,10 +15,10 @@ type Index interface {
 
 type IndexImpl struct {
 	r *core.Render
-	c service.Clock
+	c core.Clock
 }
 
-func NewIndex(r *core.Render, c service.Clock) Index {
+func NewIndex(r *core.Render, c core.Clock) Index {
 	return IndexImpl{
 		r: r,
 		c: c,
diff --git a/internal/handler/transaction.go b/internal/handler/transaction.go
index bae53ca..5e330fa 100644
--- a/internal/handler/transaction.go
+++ b/internal/handler/transaction.go
@@ -157,7 +157,7 @@ func (h TransactionImpl) handleUpdateTransaction() http.HandlerFunc {
 		if idStr != "new" {
 			id, err = uuid.Parse(idStr)
 			if err != nil {
-				core.HandleError(w, r, fmt.Errorf("could not parse Id: %w", service.ErrBadRequest))
+				core.HandleError(w, r, fmt.Errorf("could not parse Id: %w", core.ErrBadRequest))
 				return
 			}
 		}
@@ -167,7 +167,7 @@ func (h TransactionImpl) handleUpdateTransaction() http.HandlerFunc {
 		if accountIdStr != "" {
 			i, err := uuid.Parse(accountIdStr)
 			if err != nil {
-				core.HandleError(w, r, fmt.Errorf("could not parse account id: %w", service.ErrBadRequest))
+				core.HandleError(w, r, fmt.Errorf("could not parse account id: %w", core.ErrBadRequest))
 				return
 			}
 			accountId = &i
@@ -178,7 +178,7 @@ func (h TransactionImpl) handleUpdateTransaction() http.HandlerFunc {
 		if treasureChestIdStr != "" {
 			i, err := uuid.Parse(treasureChestIdStr)
 			if err != nil {
-				core.HandleError(w, r, fmt.Errorf("could not parse treasure chest id: %w", service.ErrBadRequest))
+				core.HandleError(w, r, fmt.Errorf("could not parse treasure chest id: %w", core.ErrBadRequest))
 				return
 			}
 			treasureChestId = &i
@@ -186,14 +186,14 @@ func (h TransactionImpl) handleUpdateTransaction() http.HandlerFunc {
 
 		valueF, err := strconv.ParseFloat(r.FormValue("value"), 64)
 		if err != nil {
-			core.HandleError(w, r, fmt.Errorf("could not parse value: %w", service.ErrBadRequest))
+			core.HandleError(w, r, fmt.Errorf("could not parse value: %w", core.ErrBadRequest))
 			return
 		}
 		value := int64(math.Round(valueF * service.DECIMALS_MULTIPLIER))
 
 		timestamp, err := time.Parse("2006-01-02", r.FormValue("timestamp"))
 		if err != nil {
-			core.HandleError(w, r, fmt.Errorf("could not parse timestamp: %w", service.ErrBadRequest))
+			core.HandleError(w, r, fmt.Errorf("could not parse timestamp: %w", core.ErrBadRequest))
 			return
 		}
 
diff --git a/internal/handler/transaction_recurring.go b/internal/handler/transaction_recurring.go
index 33f8a39..615d443 100644
--- a/internal/handler/transaction_recurring.go
+++ b/internal/handler/transaction_recurring.go
@@ -2,6 +2,7 @@ package handler
 
 import (
 	"net/http"
+	"spend-sparrow/internal/auth_types"
 	"spend-sparrow/internal/core"
 	"spend-sparrow/internal/service"
 	t "spend-sparrow/internal/template/transaction_recurring"
@@ -111,7 +112,7 @@ func (h TransactionRecurringImpl) handleDeleteTransactionRecurring() http.Handle
 	}
 }
 
-func (h TransactionRecurringImpl) renderItems(w http.ResponseWriter, r *http.Request, user *types.User, id, accountId, treasureChestId string) {
+func (h TransactionRecurringImpl) renderItems(w http.ResponseWriter, r *http.Request, user *auth_types.User, id, accountId, treasureChestId string) {
 	var transactionsRecurring []*types.TransactionRecurring
 	var err error
 	if accountId == "" && treasureChestId == "" {
diff --git a/internal/service/dashboard.go b/internal/service/dashboard.go
index 13235d4..187efa9 100644
--- a/internal/service/dashboard.go
+++ b/internal/service/dashboard.go
@@ -2,6 +2,8 @@ package service
 
 import (
 	"context"
+	"spend-sparrow/internal/auth_types"
+	"spend-sparrow/internal/core"
 	"spend-sparrow/internal/db"
 	"spend-sparrow/internal/types"
 	"time"
@@ -22,10 +24,10 @@ func NewDashboard(db *sqlx.DB) *Dashboard {
 
 func (s Dashboard) MainChart(
 	ctx context.Context,
-	user *types.User,
+	user *auth_types.User,
 ) ([]types.DashboardMainChartEntry, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	transactions := make([]types.Transaction, 0)
@@ -82,10 +84,10 @@ func (s Dashboard) MainChart(
 
 func (s Dashboard) TreasureChests(
 	ctx context.Context,
-	user *types.User,
+	user *auth_types.User,
 ) ([]*types.DashboardTreasureChest, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	treasureChests := make([]*types.TreasureChest, 0)
@@ -120,11 +122,11 @@ func (s Dashboard) TreasureChests(
 
 func (s Dashboard) TreasureChest(
 	ctx context.Context,
-	user *types.User,
+	user *auth_types.User,
 	treausureChestId *uuid.UUID,
 ) ([]types.DashboardMainChartEntry, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	transactions := make([]types.Transaction, 0)
diff --git a/internal/service/default.go b/internal/service/default.go
index 72d8261..b92dd39 100644
--- a/internal/service/default.go
+++ b/internal/service/default.go
@@ -3,6 +3,7 @@ package service
 import (
 	"fmt"
 	"regexp"
+	"spend-sparrow/internal/core"
 )
 
 const (
@@ -16,9 +17,9 @@ var (
 func ValidateString(value string, fieldName string) error {
 	switch {
 	case value == "":
-		return fmt.Errorf("field \"%s\" needs to be set: %w", fieldName, ErrBadRequest)
+		return fmt.Errorf("field \"%s\" needs to be set: %w", fieldName, core.ErrBadRequest)
 	case !safeInputRegex.MatchString(value):
-		return fmt.Errorf("use only letters, dashes and spaces for \"%s\": %w", fieldName, ErrBadRequest)
+		return fmt.Errorf("use only letters, dashes and spaces for \"%s\": %w", fieldName, core.ErrBadRequest)
 	default:
 		return nil
 	}
diff --git a/internal/service/error.go b/internal/service/error.go
deleted file mode 100644
index 4f5da50..0000000
--- a/internal/service/error.go
+++ /dev/null
@@ -1,8 +0,0 @@
-package service
-
-import "errors"
-
-var (
-	ErrBadRequest   = errors.New("bad request")
-	ErrUnauthorized = errors.New("unauthorized")
-)
diff --git a/internal/service/transaction.go b/internal/service/transaction.go
index f950447..fa0e3c4 100644
--- a/internal/service/transaction.go
+++ b/internal/service/transaction.go
@@ -5,6 +5,8 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
+	"spend-sparrow/internal/auth_types"
+	"spend-sparrow/internal/core"
 	"spend-sparrow/internal/db"
 	"spend-sparrow/internal/types"
 	"strconv"
@@ -17,22 +19,22 @@ import (
 const page_size = 25
 
 type Transaction interface {
-	Add(ctx context.Context, tx *sqlx.Tx, user *types.User, transaction types.Transaction) (*types.Transaction, error)
-	Update(ctx context.Context, user *types.User, transaction types.Transaction) (*types.Transaction, error)
-	Get(ctx context.Context, user *types.User, id string) (*types.Transaction, error)
-	GetAll(ctx context.Context, user *types.User, filter types.TransactionItemsFilter) ([]*types.Transaction, error)
-	Delete(ctx context.Context, user *types.User, id string) error
+	Add(ctx context.Context, tx *sqlx.Tx, user *auth_types.User, transaction types.Transaction) (*types.Transaction, error)
+	Update(ctx context.Context, user *auth_types.User, transaction types.Transaction) (*types.Transaction, error)
+	Get(ctx context.Context, user *auth_types.User, id string) (*types.Transaction, error)
+	GetAll(ctx context.Context, user *auth_types.User, filter types.TransactionItemsFilter) ([]*types.Transaction, error)
+	Delete(ctx context.Context, user *auth_types.User, id string) error
 
-	RecalculateBalances(ctx context.Context, user *types.User) error
+	RecalculateBalances(ctx context.Context, user *auth_types.User) error
 }
 
 type TransactionImpl struct {
 	db     *sqlx.DB
-	clock  Clock
-	random Random
+	clock  core.Clock
+	random core.Random
 }
 
-func NewTransaction(db *sqlx.DB, random Random, clock Clock) Transaction {
+func NewTransaction(db *sqlx.DB, random core.Random, clock core.Clock) Transaction {
 	return TransactionImpl{
 		db:     db,
 		clock:  clock,
@@ -40,9 +42,9 @@ func NewTransaction(db *sqlx.DB, random Random, clock Clock) Transaction {
 	}
 }
 
-func (s TransactionImpl) Add(ctx context.Context, tx *sqlx.Tx, user *types.User, transactionInput types.Transaction) (*types.Transaction, error) {
+func (s TransactionImpl) Add(ctx context.Context, tx *sqlx.Tx, user *auth_types.User, transactionInput types.Transaction) (*types.Transaction, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	var err error
@@ -107,9 +109,9 @@ func (s TransactionImpl) Add(ctx context.Context, tx *sqlx.Tx, user *types.User,
 	return transaction, nil
 }
 
-func (s TransactionImpl) Update(ctx context.Context, user *types.User, input types.Transaction) (*types.Transaction, error) {
+func (s TransactionImpl) Update(ctx context.Context, user *auth_types.User, input types.Transaction) (*types.Transaction, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	tx, err := s.db.BeginTxx(ctx, nil)
@@ -125,10 +127,10 @@ func (s TransactionImpl) Update(ctx context.Context, user *types.User, input typ
 	err = tx.GetContext(ctx, transaction, `SELECT * FROM "transaction" WHERE user_id = ? AND id = ?`, user.Id, input.Id)
 	err = db.TransformAndLogDbError(ctx, "transaction Update", nil, err)
 	if err != nil {
-		if errors.Is(err, db.ErrNotFound) {
-			return nil, fmt.Errorf("transaction %v not found: %w", input.Id, ErrBadRequest)
+		if errors.Is(err, core.ErrNotFound) {
+			return nil, fmt.Errorf("transaction %v not found: %w", input.Id, core.ErrBadRequest)
 		}
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	if transaction.Error == nil && transaction.AccountId != nil {
@@ -206,32 +208,32 @@ func (s TransactionImpl) Update(ctx context.Context, user *types.User, input typ
 	return transaction, nil
 }
 
-func (s TransactionImpl) Get(ctx context.Context, user *types.User, id string) (*types.Transaction, error) {
+func (s TransactionImpl) Get(ctx context.Context, user *auth_types.User, id string) (*types.Transaction, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 	uuid, err := uuid.Parse(id)
 	if err != nil {
 		slog.ErrorContext(ctx, "transaction get", "err", err)
-		return nil, fmt.Errorf("could not parse Id: %w", ErrBadRequest)
+		return nil, fmt.Errorf("could not parse Id: %w", core.ErrBadRequest)
 	}
 
 	var transaction types.Transaction
 	err = s.db.GetContext(ctx, &transaction, `SELECT * FROM "transaction" WHERE user_id = ? AND id = ?`, user.Id, uuid)
 	err = db.TransformAndLogDbError(ctx, "transaction Get", nil, err)
 	if err != nil {
-		if errors.Is(err, db.ErrNotFound) {
-			return nil, fmt.Errorf("transaction %v not found: %w", id, ErrBadRequest)
+		if errors.Is(err, core.ErrNotFound) {
+			return nil, fmt.Errorf("transaction %v not found: %w", id, core.ErrBadRequest)
 		}
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	return &transaction, nil
 }
 
-func (s TransactionImpl) GetAll(ctx context.Context, user *types.User, filter types.TransactionItemsFilter) ([]*types.Transaction, error) {
+func (s TransactionImpl) GetAll(ctx context.Context, user *auth_types.User, filter types.TransactionItemsFilter) ([]*types.Transaction, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	var (
@@ -277,14 +279,14 @@ func (s TransactionImpl) GetAll(ctx context.Context, user *types.User, filter ty
 	return transactions, nil
 }
 
-func (s TransactionImpl) Delete(ctx context.Context, user *types.User, id string) error {
+func (s TransactionImpl) Delete(ctx context.Context, user *auth_types.User, id string) error {
 	if user == nil {
-		return ErrUnauthorized
+		return core.ErrUnauthorized
 	}
 	uuid, err := uuid.Parse(id)
 	if err != nil {
 		slog.ErrorContext(ctx, "transaction delete", "err", err)
-		return fmt.Errorf("could not parse Id: %w", ErrBadRequest)
+		return fmt.Errorf("could not parse Id: %w", core.ErrBadRequest)
 	}
 
 	tx, err := s.db.BeginTxx(ctx, nil)
@@ -310,7 +312,7 @@ func (s TransactionImpl) Delete(ctx context.Context, user *types.User, id string
 			WHERE id = ?
 				AND user_id = ?`, transaction.Value, transaction.AccountId, user.Id)
 		err = db.TransformAndLogDbError(ctx, "transaction Delete", r, err)
-		if err != nil && !errors.Is(err, db.ErrNotFound) {
+		if err != nil && !errors.Is(err, core.ErrNotFound) {
 			return err
 		}
 	}
@@ -322,7 +324,7 @@ func (s TransactionImpl) Delete(ctx context.Context, user *types.User, id string
 			WHERE id = ?
 				AND user_id = ?`, transaction.Value, transaction.TreasureChestId, user.Id)
 		err = db.TransformAndLogDbError(ctx, "transaction Delete", r, err)
-		if err != nil && !errors.Is(err, db.ErrNotFound) {
+		if err != nil && !errors.Is(err, core.ErrNotFound) {
 			return err
 		}
 	}
@@ -342,9 +344,9 @@ func (s TransactionImpl) Delete(ctx context.Context, user *types.User, id string
 	return nil
 }
 
-func (s TransactionImpl) RecalculateBalances(ctx context.Context, user *types.User) error {
+func (s TransactionImpl) RecalculateBalances(ctx context.Context, user *auth_types.User) error {
 	if user == nil {
-		return ErrUnauthorized
+		return core.ErrUnauthorized
 	}
 
 	tx, err := s.db.BeginTxx(ctx, nil)
@@ -361,7 +363,7 @@ func (s TransactionImpl) RecalculateBalances(ctx context.Context, user *types.Us
 		SET current_balance = 0
 		WHERE user_id = ?`, user.Id)
 	err = db.TransformAndLogDbError(ctx, "transaction RecalculateBalances", r, err)
-	if err != nil && !errors.Is(err, db.ErrNotFound) {
+	if err != nil && !errors.Is(err, core.ErrNotFound) {
 		return err
 	}
 
@@ -370,7 +372,7 @@ func (s TransactionImpl) RecalculateBalances(ctx context.Context, user *types.Us
 		SET current_balance = 0
 		WHERE user_id = ?`, user.Id)
 	err = db.TransformAndLogDbError(ctx, "transaction RecalculateBalances", r, err)
-	if err != nil && !errors.Is(err, db.ErrNotFound) {
+	if err != nil && !errors.Is(err, core.ErrNotFound) {
 		return err
 	}
 
@@ -379,7 +381,7 @@ func (s TransactionImpl) RecalculateBalances(ctx context.Context, user *types.Us
 		FROM "transaction" 
 		WHERE user_id = ?`, user.Id)
 	err = db.TransformAndLogDbError(ctx, "transaction RecalculateBalances", nil, err)
-	if err != nil && !errors.Is(err, db.ErrNotFound) {
+	if err != nil && !errors.Is(err, core.ErrNotFound) {
 		return err
 	}
 	defer func() {
@@ -458,7 +460,7 @@ func (s TransactionImpl) validateAndEnrichTransaction(ctx context.Context, tx *s
 	if oldTransaction == nil {
 		id, err = s.random.UUID(ctx)
 		if err != nil {
-			return nil, types.ErrInternal
+			return nil, core.ErrInternal
 		}
 		createdAt = s.clock.Now()
 		createdBy = userId
@@ -479,7 +481,7 @@ func (s TransactionImpl) validateAndEnrichTransaction(ctx context.Context, tx *s
 		}
 		if rowCount == 0 {
 			slog.ErrorContext(ctx, "transaction validate", "err", err)
-			return nil, fmt.Errorf("account not found: %w", ErrBadRequest)
+			return nil, fmt.Errorf("account not found: %w", core.ErrBadRequest)
 		}
 	}
 
@@ -488,13 +490,13 @@ func (s TransactionImpl) validateAndEnrichTransaction(ctx context.Context, tx *s
 		err = tx.GetContext(ctx, &treasureChest, `SELECT * FROM treasure_chest WHERE id = ? AND user_id = ?`, input.TreasureChestId, userId)
 		err = db.TransformAndLogDbError(ctx, "transaction validate", nil, err)
 		if err != nil {
-			if errors.Is(err, db.ErrNotFound) {
-				return nil, fmt.Errorf("treasure chest not found: %w", ErrBadRequest)
+			if errors.Is(err, core.ErrNotFound) {
+				return nil, fmt.Errorf("treasure chest not found: %w", core.ErrBadRequest)
 			}
 			return nil, err
 		}
 		if treasureChest.ParentId == nil {
-			return nil, fmt.Errorf("treasure chest is a group: %w", ErrBadRequest)
+			return nil, fmt.Errorf("treasure chest is a group: %w", core.ErrBadRequest)
 		}
 	}
 
diff --git a/internal/service/transaction_recurring.go b/internal/service/transaction_recurring.go
index 6982ebc..9a6b31f 100644
--- a/internal/service/transaction_recurring.go
+++ b/internal/service/transaction_recurring.go
@@ -6,6 +6,8 @@ import (
 	"fmt"
 	"log/slog"
 	"math"
+	"spend-sparrow/internal/auth_types"
+	"spend-sparrow/internal/core"
 	"spend-sparrow/internal/db"
 	"spend-sparrow/internal/types"
 	"strconv"
@@ -16,24 +18,24 @@ import (
 )
 
 type TransactionRecurring interface {
-	Add(ctx context.Context, user *types.User, transactionRecurring types.TransactionRecurringInput) (*types.TransactionRecurring, error)
-	Update(ctx context.Context, user *types.User, transactionRecurring types.TransactionRecurringInput) (*types.TransactionRecurring, error)
-	GetAll(ctx context.Context, user *types.User) ([]*types.TransactionRecurring, error)
-	GetAllByAccount(ctx context.Context, user *types.User, accountId string) ([]*types.TransactionRecurring, error)
-	GetAllByTreasureChest(ctx context.Context, user *types.User, treasureChestId string) ([]*types.TransactionRecurring, error)
-	Delete(ctx context.Context, user *types.User, id string) error
+	Add(ctx context.Context, user *auth_types.User, transactionRecurring types.TransactionRecurringInput) (*types.TransactionRecurring, error)
+	Update(ctx context.Context, user *auth_types.User, transactionRecurring types.TransactionRecurringInput) (*types.TransactionRecurring, error)
+	GetAll(ctx context.Context, user *auth_types.User) ([]*types.TransactionRecurring, error)
+	GetAllByAccount(ctx context.Context, user *auth_types.User, accountId string) ([]*types.TransactionRecurring, error)
+	GetAllByTreasureChest(ctx context.Context, user *auth_types.User, treasureChestId string) ([]*types.TransactionRecurring, error)
+	Delete(ctx context.Context, user *auth_types.User, id string) error
 
 	GenerateTransactions(ctx context.Context) error
 }
 
 type TransactionRecurringImpl struct {
 	db          *sqlx.DB
-	clock       Clock
-	random      Random
+	clock       core.Clock
+	random      core.Random
 	transaction Transaction
 }
 
-func NewTransactionRecurring(db *sqlx.DB, random Random, clock Clock, transaction Transaction) TransactionRecurring {
+func NewTransactionRecurring(db *sqlx.DB, random core.Random, clock core.Clock, transaction Transaction) TransactionRecurring {
 	return TransactionRecurringImpl{
 		db:          db,
 		clock:       clock,
@@ -43,11 +45,11 @@ func NewTransactionRecurring(db *sqlx.DB, random Random, clock Clock, transactio
 }
 
 func (s TransactionRecurringImpl) Add(ctx context.Context,
-	user *types.User,
+	user *auth_types.User,
 	transactionRecurringInput types.TransactionRecurringInput,
 ) (*types.TransactionRecurring, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	tx, err := s.db.BeginTxx(ctx, nil)
@@ -85,16 +87,16 @@ func (s TransactionRecurringImpl) Add(ctx context.Context,
 }
 
 func (s TransactionRecurringImpl) Update(ctx context.Context,
-	user *types.User,
+	user *auth_types.User,
 	input types.TransactionRecurringInput,
 ) (*types.TransactionRecurring, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 	uuid, err := uuid.Parse(input.Id)
 	if err != nil {
 		slog.ErrorContext(ctx, "transactionRecurring update", "err", err)
-		return nil, fmt.Errorf("could not parse Id: %w", ErrBadRequest)
+		return nil, fmt.Errorf("could not parse Id: %w", core.ErrBadRequest)
 	}
 
 	tx, err := s.db.BeginTxx(ctx, nil)
@@ -110,10 +112,10 @@ func (s TransactionRecurringImpl) Update(ctx context.Context,
 	err = tx.GetContext(ctx, transactionRecurring, `SELECT * FROM transaction_recurring WHERE user_id = ? AND id = ?`, user.Id, uuid)
 	err = db.TransformAndLogDbError(ctx, "transactionRecurring Update", nil, err)
 	if err != nil {
-		if errors.Is(err, db.ErrNotFound) {
-			return nil, fmt.Errorf("transactionRecurring %v not found: %w", input.Id, ErrBadRequest)
+		if errors.Is(err, core.ErrNotFound) {
+			return nil, fmt.Errorf("transactionRecurring %v not found: %w", input.Id, core.ErrBadRequest)
 		}
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	transactionRecurring, err = s.validateAndEnrichTransactionRecurring(ctx, tx, transactionRecurring, user.Id, input)
@@ -149,9 +151,9 @@ func (s TransactionRecurringImpl) Update(ctx context.Context,
 	return transactionRecurring, nil
 }
 
-func (s TransactionRecurringImpl) GetAll(ctx context.Context, user *types.User) ([]*types.TransactionRecurring, error) {
+func (s TransactionRecurringImpl) GetAll(ctx context.Context, user *auth_types.User) ([]*types.TransactionRecurring, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	transactionRecurrings := make([]*types.TransactionRecurring, 0)
@@ -169,15 +171,15 @@ func (s TransactionRecurringImpl) GetAll(ctx context.Context, user *types.User)
 	return transactionRecurrings, nil
 }
 
-func (s TransactionRecurringImpl) GetAllByAccount(ctx context.Context, user *types.User, accountId string) ([]*types.TransactionRecurring, error) {
+func (s TransactionRecurringImpl) GetAllByAccount(ctx context.Context, user *auth_types.User, accountId string) ([]*types.TransactionRecurring, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	accountUuid, err := uuid.Parse(accountId)
 	if err != nil {
 		slog.ErrorContext(ctx, "transactionRecurring GetAllByAccount", "err", err)
-		return nil, fmt.Errorf("could not parse accountId: %w", ErrBadRequest)
+		return nil, fmt.Errorf("could not parse accountId: %w", core.ErrBadRequest)
 	}
 
 	tx, err := s.db.BeginTxx(ctx, nil)
@@ -193,10 +195,10 @@ func (s TransactionRecurringImpl) GetAllByAccount(ctx context.Context, user *typ
 	err = tx.GetContext(ctx, &rowCount, `SELECT COUNT(*) FROM account WHERE id = ? AND user_id = ?`, accountUuid, user.Id)
 	err = db.TransformAndLogDbError(ctx, "transactionRecurring GetAllByAccount", nil, err)
 	if err != nil {
-		if errors.Is(err, db.ErrNotFound) {
-			return nil, fmt.Errorf("account %v not found: %w", accountId, ErrBadRequest)
+		if errors.Is(err, core.ErrNotFound) {
+			return nil, fmt.Errorf("account %v not found: %w", accountId, core.ErrBadRequest)
 		}
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	transactionRecurrings := make([]*types.TransactionRecurring, 0)
@@ -222,17 +224,17 @@ func (s TransactionRecurringImpl) GetAllByAccount(ctx context.Context, user *typ
 }
 
 func (s TransactionRecurringImpl) GetAllByTreasureChest(ctx context.Context,
-	user *types.User,
+	user *auth_types.User,
 	treasureChestId string,
 ) ([]*types.TransactionRecurring, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	treasureChestUuid, err := uuid.Parse(treasureChestId)
 	if err != nil {
 		slog.ErrorContext(ctx, "transactionRecurring GetAllByTreasureChest", "err", err)
-		return nil, fmt.Errorf("could not parse treasureChestId: %w", ErrBadRequest)
+		return nil, fmt.Errorf("could not parse treasureChestId: %w", core.ErrBadRequest)
 	}
 
 	tx, err := s.db.BeginTxx(ctx, nil)
@@ -248,10 +250,10 @@ func (s TransactionRecurringImpl) GetAllByTreasureChest(ctx context.Context,
 	err = tx.GetContext(ctx, &rowCount, `SELECT COUNT(*) FROM treasure_chest WHERE id = ? AND user_id = ?`, treasureChestId, user.Id)
 	err = db.TransformAndLogDbError(ctx, "transactionRecurring GetAllByTreasureChest", nil, err)
 	if err != nil {
-		if errors.Is(err, db.ErrNotFound) {
-			return nil, fmt.Errorf("treasurechest %v not found: %w", treasureChestId, ErrBadRequest)
+		if errors.Is(err, core.ErrNotFound) {
+			return nil, fmt.Errorf("treasurechest %v not found: %w", treasureChestId, core.ErrBadRequest)
 		}
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	transactionRecurrings := make([]*types.TransactionRecurring, 0)
@@ -276,14 +278,14 @@ func (s TransactionRecurringImpl) GetAllByTreasureChest(ctx context.Context,
 	return transactionRecurrings, nil
 }
 
-func (s TransactionRecurringImpl) Delete(ctx context.Context, user *types.User, id string) error {
+func (s TransactionRecurringImpl) Delete(ctx context.Context, user *auth_types.User, id string) error {
 	if user == nil {
-		return ErrUnauthorized
+		return core.ErrUnauthorized
 	}
 	uuid, err := uuid.Parse(id)
 	if err != nil {
 		slog.ErrorContext(ctx, "transactionRecurring delete", "err", err)
-		return fmt.Errorf("could not parse Id: %w", ErrBadRequest)
+		return fmt.Errorf("could not parse Id: %w", core.ErrBadRequest)
 	}
 
 	tx, err := s.db.BeginTxx(ctx, nil)
@@ -339,7 +341,7 @@ func (s TransactionRecurringImpl) GenerateTransactions(ctx context.Context) erro
 	}
 
 	for _, transactionRecurring := range recurringTransactions {
-		user := &types.User{
+		user := &auth_types.User{
 			Id: transactionRecurring.UserId,
 		}
 		transaction := types.Transaction{
@@ -397,7 +399,7 @@ func (s TransactionRecurringImpl) validateAndEnrichTransactionRecurring(
 	if oldTransactionRecurring == nil {
 		id, err = s.random.UUID(ctx)
 		if err != nil {
-			return nil, types.ErrInternal
+			return nil, core.ErrInternal
 		}
 		createdAt = s.clock.Now()
 		createdBy = userId
@@ -416,7 +418,7 @@ func (s TransactionRecurringImpl) validateAndEnrichTransactionRecurring(
 		temp, err := uuid.Parse(input.AccountId)
 		if err != nil {
 			slog.ErrorContext(ctx, "transactionRecurring validate", "err", err)
-			return nil, fmt.Errorf("could not parse accountId: %w", ErrBadRequest)
+			return nil, fmt.Errorf("could not parse accountId: %w", core.ErrBadRequest)
 		}
 		accountUuid = &temp
 		err = tx.GetContext(ctx, &rowCount, `SELECT COUNT(*) FROM account WHERE id = ? AND user_id = ?`, accountUuid, userId)
@@ -426,7 +428,7 @@ func (s TransactionRecurringImpl) validateAndEnrichTransactionRecurring(
 		}
 		if rowCount == 0 {
 			slog.ErrorContext(ctx, "transactionRecurring validate", "err", err)
-			return nil, fmt.Errorf("account not found: %w", ErrBadRequest)
+			return nil, fmt.Errorf("account not found: %w", core.ErrBadRequest)
 		}
 
 		hasAccount = true
@@ -436,37 +438,37 @@ func (s TransactionRecurringImpl) validateAndEnrichTransactionRecurring(
 		temp, err := uuid.Parse(input.TreasureChestId)
 		if err != nil {
 			slog.ErrorContext(ctx, "transactionRecurring validate", "err", err)
-			return nil, fmt.Errorf("could not parse treasureChestId: %w", ErrBadRequest)
+			return nil, fmt.Errorf("could not parse treasureChestId: %w", core.ErrBadRequest)
 		}
 		treasureChestUuid = &temp
 		var treasureChest types.TreasureChest
 		err = tx.GetContext(ctx, &treasureChest, `SELECT * FROM treasure_chest WHERE id = ? AND user_id = ?`, treasureChestUuid, userId)
 		err = db.TransformAndLogDbError(ctx, "transactionRecurring validate", nil, err)
 		if err != nil {
-			if errors.Is(err, db.ErrNotFound) {
-				return nil, fmt.Errorf("treasure chest not found: %w", ErrBadRequest)
+			if errors.Is(err, core.ErrNotFound) {
+				return nil, fmt.Errorf("treasure chest not found: %w", core.ErrBadRequest)
 			}
 			return nil, err
 		}
 		if treasureChest.ParentId == nil {
-			return nil, fmt.Errorf("treasure chest is a group: %w", ErrBadRequest)
+			return nil, fmt.Errorf("treasure chest is a group: %w", core.ErrBadRequest)
 		}
 		hasTreasureChest = true
 	}
 
 	if !hasAccount && !hasTreasureChest {
 		slog.ErrorContext(ctx, "transactionRecurring validate", "err", err)
-		return nil, fmt.Errorf("either account or treasure chest is required: %w", ErrBadRequest)
+		return nil, fmt.Errorf("either account or treasure chest is required: %w", core.ErrBadRequest)
 	}
 	if hasAccount && hasTreasureChest {
 		slog.ErrorContext(ctx, "transactionRecurring validate", "err", err)
-		return nil, fmt.Errorf("either account or treasure chest is required, not both: %w", ErrBadRequest)
+		return nil, fmt.Errorf("either account or treasure chest is required, not both: %w", core.ErrBadRequest)
 	}
 
 	valueFloat, err := strconv.ParseFloat(input.Value, 64)
 	if err != nil {
 		slog.ErrorContext(ctx, "transactionRecurring validate", "err", err)
-		return nil, fmt.Errorf("could not parse value: %w", ErrBadRequest)
+		return nil, fmt.Errorf("could not parse value: %w", core.ErrBadRequest)
 	}
 	value := int64(math.Round(valueFloat * DECIMALS_MULTIPLIER))
 
@@ -485,18 +487,18 @@ func (s TransactionRecurringImpl) validateAndEnrichTransactionRecurring(
 	intervalMonths, err = strconv.ParseInt(input.IntervalMonths, 10, 0)
 	if err != nil {
 		slog.ErrorContext(ctx, "transactionRecurring validate", "err", err)
-		return nil, fmt.Errorf("could not parse intervalMonths: %w", ErrBadRequest)
+		return nil, fmt.Errorf("could not parse intervalMonths: %w", core.ErrBadRequest)
 	}
 	if intervalMonths < 1 {
 		slog.ErrorContext(ctx, "transactionRecurring validate", "err", err)
-		return nil, fmt.Errorf("intervalMonths needs to be greater than 0: %w", ErrBadRequest)
+		return nil, fmt.Errorf("intervalMonths needs to be greater than 0: %w", core.ErrBadRequest)
 	}
 	var nextExecution *time.Time = nil
 	if input.NextExecution != "" {
 		t, err := time.Parse("2006-01-02", input.NextExecution)
 		if err != nil {
 			slog.ErrorContext(ctx, "transaction validate", "err", err)
-			return nil, fmt.Errorf("could not parse timestamp: %w", ErrBadRequest)
+			return nil, fmt.Errorf("could not parse timestamp: %w", core.ErrBadRequest)
 		}
 
 		t = time.Date(t.Year(), t.Month(), 1, 0, 0, 0, 0, t.Location())
diff --git a/internal/service/treasure_chest.go b/internal/service/treasure_chest.go
index cdc60b5..65db751 100644
--- a/internal/service/treasure_chest.go
+++ b/internal/service/treasure_chest.go
@@ -6,6 +6,8 @@ import (
 	"fmt"
 	"log/slog"
 	"slices"
+	"spend-sparrow/internal/auth_types"
+	"spend-sparrow/internal/core"
 	"spend-sparrow/internal/db"
 	"spend-sparrow/internal/types"
 
@@ -14,20 +16,20 @@ import (
 )
 
 type TreasureChest interface {
-	Add(ctx context.Context, user *types.User, parentId, name string) (*types.TreasureChest, error)
-	Update(ctx context.Context, user *types.User, id, parentId, name string) (*types.TreasureChest, error)
-	Get(ctx context.Context, user *types.User, id string) (*types.TreasureChest, error)
-	GetAll(ctx context.Context, user *types.User) ([]*types.TreasureChest, error)
-	Delete(ctx context.Context, user *types.User, id string) error
+	Add(ctx context.Context, user *auth_types.User, parentId, name string) (*types.TreasureChest, error)
+	Update(ctx context.Context, user *auth_types.User, id, parentId, name string) (*types.TreasureChest, error)
+	Get(ctx context.Context, user *auth_types.User, id string) (*types.TreasureChest, error)
+	GetAll(ctx context.Context, user *auth_types.User) ([]*types.TreasureChest, error)
+	Delete(ctx context.Context, user *auth_types.User, id string) error
 }
 
 type TreasureChestImpl struct {
 	db     *sqlx.DB
-	clock  Clock
-	random Random
+	clock  core.Clock
+	random core.Random
 }
 
-func NewTreasureChest(db *sqlx.DB, random Random, clock Clock) TreasureChest {
+func NewTreasureChest(db *sqlx.DB, random core.Random, clock core.Clock) TreasureChest {
 	return TreasureChestImpl{
 		db:     db,
 		clock:  clock,
@@ -35,14 +37,14 @@ func NewTreasureChest(db *sqlx.DB, random Random, clock Clock) TreasureChest {
 	}
 }
 
-func (s TreasureChestImpl) Add(ctx context.Context, user *types.User, parentId, name string) (*types.TreasureChest, error) {
+func (s TreasureChestImpl) Add(ctx context.Context, user *auth_types.User, parentId, name string) (*types.TreasureChest, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	newId, err := s.random.UUID(ctx)
 	if err != nil {
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	err = ValidateString(name, "name")
@@ -57,7 +59,7 @@ func (s TreasureChestImpl) Add(ctx context.Context, user *types.User, parentId,
 			return nil, err
 		}
 		if parent.ParentId != nil {
-			return nil, fmt.Errorf("only a depth of 1 allowed: %w", ErrBadRequest)
+			return nil, fmt.Errorf("only a depth of 1 allowed: %w", core.ErrBadRequest)
 		}
 		parentUuid = &parent.Id
 	}
@@ -88,9 +90,9 @@ func (s TreasureChestImpl) Add(ctx context.Context, user *types.User, parentId,
 	return treasureChest, nil
 }
 
-func (s TreasureChestImpl) Update(ctx context.Context, user *types.User, idStr, parentId, name string) (*types.TreasureChest, error) {
+func (s TreasureChestImpl) Update(ctx context.Context, user *auth_types.User, idStr, parentId, name string) (*types.TreasureChest, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 	err := ValidateString(name, "name")
 	if err != nil {
@@ -99,7 +101,7 @@ func (s TreasureChestImpl) Update(ctx context.Context, user *types.User, idStr,
 	id, err := uuid.Parse(idStr)
 	if err != nil {
 		slog.ErrorContext(ctx, "treasureChest update", "err", err)
-		return nil, fmt.Errorf("could not parse Id: %w", ErrBadRequest)
+		return nil, fmt.Errorf("could not parse Id: %w", core.ErrBadRequest)
 	}
 
 	tx, err := s.db.BeginTxx(ctx, nil)
@@ -115,10 +117,10 @@ func (s TreasureChestImpl) Update(ctx context.Context, user *types.User, idStr,
 	err = tx.GetContext(ctx, treasureChest, `SELECT * FROM treasure_chest WHERE user_id = ? AND id = ?`, user.Id, id)
 	err = db.TransformAndLogDbError(ctx, "treasureChest Update", nil, err)
 	if err != nil {
-		if errors.Is(err, db.ErrNotFound) {
+		if errors.Is(err, core.ErrNotFound) {
 			return nil, fmt.Errorf("treasureChest %v not found: %w", idStr, err)
 		}
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	var parentUuid *uuid.UUID
@@ -134,7 +136,7 @@ func (s TreasureChestImpl) Update(ctx context.Context, user *types.User, idStr,
 			return nil, err
 		}
 		if parent.ParentId != nil || childCount > 0 {
-			return nil, fmt.Errorf("only one level allowed: %w", ErrBadRequest)
+			return nil, fmt.Errorf("only one level allowed: %w", core.ErrBadRequest)
 		}
 
 		parentUuid = &parent.Id
@@ -170,32 +172,32 @@ func (s TreasureChestImpl) Update(ctx context.Context, user *types.User, idStr,
 	return treasureChest, nil
 }
 
-func (s TreasureChestImpl) Get(ctx context.Context, user *types.User, id string) (*types.TreasureChest, error) {
+func (s TreasureChestImpl) Get(ctx context.Context, user *auth_types.User, id string) (*types.TreasureChest, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 	uuid, err := uuid.Parse(id)
 	if err != nil {
 		slog.ErrorContext(ctx, "treasureChest get", "err", err)
-		return nil, fmt.Errorf("could not parse Id: %w", ErrBadRequest)
+		return nil, fmt.Errorf("could not parse Id: %w", core.ErrBadRequest)
 	}
 
 	var treasureChest types.TreasureChest
 	err = s.db.GetContext(ctx, &treasureChest, `SELECT * FROM treasure_chest WHERE user_id = ? AND id = ?`, user.Id, uuid)
 	err = db.TransformAndLogDbError(ctx, "treasureChest Get", nil, err)
 	if err != nil {
-		if errors.Is(err, db.ErrNotFound) {
+		if errors.Is(err, core.ErrNotFound) {
 			return nil, fmt.Errorf("treasureChest %v not found: %w", id, err)
 		}
-		return nil, types.ErrInternal
+		return nil, core.ErrInternal
 	}
 
 	return &treasureChest, nil
 }
 
-func (s TreasureChestImpl) GetAll(ctx context.Context, user *types.User) ([]*types.TreasureChest, error) {
+func (s TreasureChestImpl) GetAll(ctx context.Context, user *auth_types.User) ([]*types.TreasureChest, error) {
 	if user == nil {
-		return nil, ErrUnauthorized
+		return nil, core.ErrUnauthorized
 	}
 
 	treasureChests := make([]*types.TreasureChest, 0)
@@ -208,14 +210,14 @@ func (s TreasureChestImpl) GetAll(ctx context.Context, user *types.User) ([]*typ
 	return sortTreasureChests(treasureChests), nil
 }
 
-func (s TreasureChestImpl) Delete(ctx context.Context, user *types.User, idStr string) error {
+func (s TreasureChestImpl) Delete(ctx context.Context, user *auth_types.User, idStr string) error {
 	if user == nil {
-		return ErrUnauthorized
+		return core.ErrUnauthorized
 	}
 	id, err := uuid.Parse(idStr)
 	if err != nil {
 		slog.ErrorContext(ctx, "treasureChest delete", "err", err)
-		return fmt.Errorf("could not parse Id: %w", ErrBadRequest)
+		return fmt.Errorf("could not parse Id: %w", core.ErrBadRequest)
 	}
 
 	tx, err := s.db.BeginTxx(ctx, nil)
@@ -235,7 +237,7 @@ func (s TreasureChestImpl) Delete(ctx context.Context, user *types.User, idStr s
 	}
 
 	if childCount > 0 {
-		return fmt.Errorf("treasure chest has children: %w", ErrBadRequest)
+		return fmt.Errorf("treasure chest has children: %w", core.ErrBadRequest)
 	}
 
 	transactionsCount := 0
@@ -247,7 +249,7 @@ func (s TreasureChestImpl) Delete(ctx context.Context, user *types.User, idStr s
 		return err
 	}
 	if transactionsCount > 0 {
-		return fmt.Errorf("treasure chest has transactions: %w", ErrBadRequest)
+		return fmt.Errorf("treasure chest has transactions: %w", core.ErrBadRequest)
 	}
 
 	recurringCount := 0
@@ -259,7 +261,7 @@ func (s TreasureChestImpl) Delete(ctx context.Context, user *types.User, idStr s
 		return err
 	}
 	if recurringCount > 0 {
-		return fmt.Errorf("cannot delete treasure chest with existing recurring transactions: %w", ErrBadRequest)
+		return fmt.Errorf("cannot delete treasure chest with existing recurring transactions: %w", core.ErrBadRequest)
 	}
 
 	r, err := tx.ExecContext(ctx, `DELETE FROM treasure_chest WHERE id = ? AND user_id = ?`, id, user.Id)
diff --git a/internal/template/auth/default.go b/internal/template/auth/default.go
deleted file mode 100644
index 8832b06..0000000
--- a/internal/template/auth/default.go
+++ /dev/null
@@ -1 +0,0 @@
-package auth
diff --git a/internal/types/types.go b/internal/types/types.go
deleted file mode 100644
index 88d3af4..0000000
--- a/internal/types/types.go
+++ /dev/null
@@ -1,10 +0,0 @@
-package types
-
-import (
-	"errors"
-)
-
-var (
-	ErrInternal     = errors.New("internal server error")
-	ErrUnauthorized = errors.New("you are not authorized to perform this action")
-)
diff --git a/mocks/default.go b/mocks/default.go
deleted file mode 100644
index f726b26..0000000
--- a/mocks/default.go
+++ /dev/null
@@ -1 +0,0 @@
-package mocks
diff --git a/test/auth_it_test.go b/test/auth_it_test.go
index 44be9d1..59d71d4 100644
--- a/test/auth_it_test.go
+++ b/test/auth_it_test.go
@@ -2,8 +2,10 @@ package test_test
 
 import (
 	"context"
+	"spend-sparrow/internal/auth_types"
+	"spend-sparrow/internal/authentication"
+	"spend-sparrow/internal/core"
 	"spend-sparrow/internal/db"
-	"spend-sparrow/internal/types"
 	"testing"
 	"time"
 
@@ -42,11 +44,11 @@ func TestUser(t *testing.T) {
 		t.Parallel()
 		d := setupDb(t)
 
-		underTest := db.NewAuthSqlite(d)
+		underTest := authentication.NewDbSqlite(d)
 
 		verifiedAt := time.Date(2020, 1, 5, 13, 0, 0, 0, time.UTC)
 		createAt := time.Date(2020, 1, 5, 12, 0, 0, 0, time.UTC)
-		expected := types.NewUser(uuid.New(), "some@email.de", true, &verifiedAt, false, []byte("somePass"), []byte("someSalt"), createAt)
+		expected := auth_types.NewUser(uuid.New(), "some@email.de", true, &verifiedAt, false, []byte("somePass"), []byte("someSalt"), createAt)
 
 		err := underTest.InsertUser(context.Background(), expected)
 		require.NoError(t, err)
@@ -63,38 +65,38 @@ func TestUser(t *testing.T) {
 		t.Parallel()
 		d := setupDb(t)
 
-		underTest := db.NewAuthSqlite(d)
+		underTest := authentication.NewDbSqlite(d)
 
 		_, err := underTest.GetUserByEmail(context.Background(), "nonExistentEmail")
-		assert.Equal(t, db.ErrNotFound, err)
+		assert.Equal(t, core.ErrNotFound, err)
 	})
 	t.Run("should return ErrUserExist", func(t *testing.T) {
 		t.Parallel()
 		d := setupDb(t)
 
-		underTest := db.NewAuthSqlite(d)
+		underTest := authentication.NewDbSqlite(d)
 
 		verifiedAt := time.Date(2020, 1, 5, 13, 0, 0, 0, time.UTC)
 		createAt := time.Date(2020, 1, 5, 12, 0, 0, 0, time.UTC)
-		user := types.NewUser(uuid.New(), "some@email.de", true, &verifiedAt, false, []byte("somePass"), []byte("someSalt"), createAt)
+		user := auth_types.NewUser(uuid.New(), "some@email.de", true, &verifiedAt, false, []byte("somePass"), []byte("someSalt"), createAt)
 
 		err := underTest.InsertUser(context.Background(), user)
 		require.NoError(t, err)
 
 		err = underTest.InsertUser(context.Background(), user)
-		assert.Equal(t, db.ErrAlreadyExists, err)
+		assert.Equal(t, core.ErrAlreadyExists, err)
 	})
 	t.Run("should return ErrInternal on missing NOT NULL fields", func(t *testing.T) {
 		t.Parallel()
 		d := setupDb(t)
 
-		underTest := db.NewAuthSqlite(d)
+		underTest := authentication.NewDbSqlite(d)
 
 		createAt := time.Date(2020, 1, 5, 12, 0, 0, 0, time.UTC)
-		user := types.NewUser(uuid.New(), "some@email.de", false, nil, false, []byte("somePass"), nil, createAt)
+		user := auth_types.NewUser(uuid.New(), "some@email.de", false, nil, false, []byte("somePass"), nil, createAt)
 
 		err := underTest.InsertUser(context.Background(), user)
-		assert.Equal(t, types.ErrInternal, err)
+		assert.Equal(t, core.ErrInternal, err)
 	})
 }
 
@@ -105,11 +107,11 @@ func TestToken(t *testing.T) {
 		t.Parallel()
 		d := setupDb(t)
 
-		underTest := db.NewAuthSqlite(d)
+		underTest := authentication.NewDbSqlite(d)
 
 		createAt := time.Date(2020, 1, 5, 12, 0, 0, 0, time.UTC)
 		expiresAt := createAt.Add(24 * time.Hour)
-		expected := types.NewToken(uuid.New(), "sessionId", "token", types.TokenTypeCsrf, createAt, expiresAt)
+		expected := auth_types.NewToken(uuid.New(), "sessionId", "token", auth_types.TokenTypeCsrf, createAt, expiresAt)
 
 		err := underTest.InsertToken(context.Background(), expected)
 		require.NoError(t, err)
@@ -121,25 +123,25 @@ func TestToken(t *testing.T) {
 		expected.SessionId = ""
 		actuals, err := underTest.GetTokensByUserIdAndType(context.Background(), expected.UserId, expected.Type)
 		require.NoError(t, err)
-		assert.Equal(t, []*types.Token{expected}, actuals)
+		assert.Equal(t, []*auth_types.Token{expected}, actuals)
 
 		expected.SessionId = "sessionId"
 		expected.UserId = uuid.Nil
 		actuals, err = underTest.GetTokensBySessionIdAndType(context.Background(), expected.SessionId, expected.Type)
 		require.NoError(t, err)
-		assert.Equal(t, []*types.Token{expected}, actuals)
+		assert.Equal(t, []*auth_types.Token{expected}, actuals)
 	})
 	t.Run("should insert and return multiple tokens", func(t *testing.T) {
 		t.Parallel()
 		d := setupDb(t)
 
-		underTest := db.NewAuthSqlite(d)
+		underTest := authentication.NewDbSqlite(d)
 
 		createAt := time.Date(2020, 1, 5, 12, 0, 0, 0, time.UTC)
 		expiresAt := createAt.Add(24 * time.Hour)
 		userId := uuid.New()
-		expected1 := types.NewToken(userId, "sessionId", "token1", types.TokenTypeCsrf, createAt, expiresAt)
-		expected2 := types.NewToken(userId, "sessionId", "token2", types.TokenTypeCsrf, createAt, expiresAt)
+		expected1 := auth_types.NewToken(userId, "sessionId", "token1", auth_types.TokenTypeCsrf, createAt, expiresAt)
+		expected2 := auth_types.NewToken(userId, "sessionId", "token2", auth_types.TokenTypeCsrf, createAt, expiresAt)
 
 		err := underTest.InsertToken(context.Background(), expected1)
 		require.NoError(t, err)
@@ -150,7 +152,7 @@ func TestToken(t *testing.T) {
 		expected2.UserId = uuid.Nil
 		actuals, err := underTest.GetTokensBySessionIdAndType(context.Background(), expected1.SessionId, expected1.Type)
 		require.NoError(t, err)
-		assert.Equal(t, []*types.Token{expected1, expected2}, actuals)
+		assert.Equal(t, []*auth_types.Token{expected1, expected2}, actuals)
 
 		expected1.SessionId = ""
 		expected2.SessionId = ""
@@ -158,49 +160,49 @@ func TestToken(t *testing.T) {
 		expected2.UserId = userId
 		actuals, err = underTest.GetTokensByUserIdAndType(context.Background(), userId, expected1.Type)
 		require.NoError(t, err)
-		assert.Equal(t, []*types.Token{expected1, expected2}, actuals)
+		assert.Equal(t, []*auth_types.Token{expected1, expected2}, actuals)
 	})
 	t.Run("should return ErrNotFound", func(t *testing.T) {
 		t.Parallel()
 		d := setupDb(t)
 
-		underTest := db.NewAuthSqlite(d)
+		underTest := authentication.NewDbSqlite(d)
 
 		_, err := underTest.GetToken(context.Background(), "nonExistent")
-		assert.Equal(t, db.ErrNotFound, err)
+		assert.Equal(t, core.ErrNotFound, err)
 
-		_, err = underTest.GetTokensByUserIdAndType(context.Background(), uuid.New(), types.TokenTypeEmailVerify)
-		assert.Equal(t, db.ErrNotFound, err)
+		_, err = underTest.GetTokensByUserIdAndType(context.Background(), uuid.New(), auth_types.TokenTypeEmailVerify)
+		assert.Equal(t, core.ErrNotFound, err)
 
-		_, err = underTest.GetTokensBySessionIdAndType(context.Background(), "sessionId", types.TokenTypeEmailVerify)
-		assert.Equal(t, db.ErrNotFound, err)
+		_, err = underTest.GetTokensBySessionIdAndType(context.Background(), "sessionId", auth_types.TokenTypeEmailVerify)
+		assert.Equal(t, core.ErrNotFound, err)
 	})
 	t.Run("should return ErrAlreadyExists", func(t *testing.T) {
 		t.Parallel()
 		d := setupDb(t)
 
-		underTest := db.NewAuthSqlite(d)
+		underTest := authentication.NewDbSqlite(d)
 
 		verifiedAt := time.Date(2020, 1, 5, 13, 0, 0, 0, time.UTC)
 		createAt := time.Date(2020, 1, 5, 12, 0, 0, 0, time.UTC)
-		user := types.NewUser(uuid.New(), "some@email.de", true, &verifiedAt, false, []byte("somePass"), []byte("someSalt"), createAt)
+		user := auth_types.NewUser(uuid.New(), "some@email.de", true, &verifiedAt, false, []byte("somePass"), []byte("someSalt"), createAt)
 
 		err := underTest.InsertUser(context.Background(), user)
 		require.NoError(t, err)
 
 		err = underTest.InsertUser(context.Background(), user)
-		assert.Equal(t, db.ErrAlreadyExists, err)
+		assert.Equal(t, core.ErrAlreadyExists, err)
 	})
 	t.Run("should return ErrInternal on missing NOT NULL fields", func(t *testing.T) {
 		t.Parallel()
 		d := setupDb(t)
 
-		underTest := db.NewAuthSqlite(d)
+		underTest := authentication.NewDbSqlite(d)
 
 		createAt := time.Date(2020, 1, 5, 12, 0, 0, 0, time.UTC)
-		user := types.NewUser(uuid.New(), "some@email.de", false, nil, false, []byte("somePass"), nil, createAt)
+		user := auth_types.NewUser(uuid.New(), "some@email.de", false, nil, false, []byte("somePass"), nil, createAt)
 
 		err := underTest.InsertUser(context.Background(), user)
-		assert.Equal(t, types.ErrInternal, err)
+		assert.Equal(t, core.ErrInternal, err)
 	})
 }
diff --git a/test/auth_test.go b/test/auth_test.go
index f8a1ea5..1b3a5c7 100644
--- a/test/auth_test.go
+++ b/test/auth_test.go
@@ -2,8 +2,9 @@ package test_test
 
 import (
 	"context"
-	"spend-sparrow/internal/db"
-	"spend-sparrow/internal/service"
+	"spend-sparrow/internal/auth_types"
+	"spend-sparrow/internal/authentication"
+	"spend-sparrow/internal/core"
 	"spend-sparrow/internal/types"
 	"spend-sparrow/mocks"
 	"strings"
@@ -30,26 +31,26 @@ func TestSignUp(t *testing.T) {
 	t.Run("should check for correct email address", func(t *testing.T) {
 		t.Parallel()
 
-		mockAuthDb := mocks.NewMockAuth(t)
+		mockAuthDb := mocks.NewMockDb(t)
 		mockRandom := mocks.NewMockRandom(t)
 		mockClock := mocks.NewMockClock(t)
 		mockMail := mocks.NewMockMail(t)
 
-		underTest := service.NewAuth(mockAuthDb, mockRandom, mockClock, mockMail, &settings)
+		underTest := authentication.NewService(mockAuthDb, mockRandom, mockClock, mockMail, &settings)
 
 		_, err := underTest.SignUp(context.Background(), "invalid email address", "SomeStrongPassword123!")
 
-		assert.Equal(t, service.ErrInvalidEmail, err)
+		assert.Equal(t, authentication.ErrInvalidEmail, err)
 	})
 	t.Run("should check for password complexity", func(t *testing.T) {
 		t.Parallel()
 
-		mockAuthDb := mocks.NewMockAuth(t)
+		mockAuthDb := mocks.NewMockDb(t)
 		mockRandom := mocks.NewMockRandom(t)
 		mockClock := mocks.NewMockClock(t)
 		mockMail := mocks.NewMockMail(t)
 
-		underTest := service.NewAuth(mockAuthDb, mockRandom, mockClock, mockMail, &settings)
+		underTest := authentication.NewService(mockAuthDb, mockRandom, mockClock, mockMail, &settings)
 
 		weakPasswords := []string{
 			"123!ab", // too short
@@ -60,13 +61,13 @@ func TestSignUp(t *testing.T) {
 
 		for _, password := range weakPasswords {
 			_, err := underTest.SignUp(context.Background(), "some@valid.email", password)
-			assert.Equal(t, service.ErrInvalidPassword, err)
+			assert.Equal(t, authentication.ErrInvalidPassword, err)
 		}
 	})
 	t.Run("should signup correctly", func(t *testing.T) {
 		t.Parallel()
 
-		mockAuthDb := mocks.NewMockAuth(t)
+		mockAuthDb := mocks.NewMockDb(t)
 		mockRandom := mocks.NewMockRandom(t)
 		mockClock := mocks.NewMockClock(t)
 		mockMail := mocks.NewMockMail(t)
@@ -77,7 +78,7 @@ func TestSignUp(t *testing.T) {
 		salt := []byte("salt")
 		createTime := time.Date(2020, 1, 1, 0, 0, 0, 0, time.UTC)
 
-		expected := types.NewUser(userId, email, false, nil, false, service.GetHashPassword(password, salt), salt, createTime)
+		expected := auth_types.NewUser(userId, email, false, nil, false, authentication.GetHashPassword(password, salt), salt, createTime)
 
 		ctx := context.Background()
 
@@ -86,7 +87,7 @@ func TestSignUp(t *testing.T) {
 		mockClock.EXPECT().Now().Return(createTime)
 		mockAuthDb.EXPECT().InsertUser(context.Background(), expected).Return(nil)
 
-		underTest := service.NewAuth(mockAuthDb, mockRandom, mockClock, mockMail, &settings)
+		underTest := authentication.NewService(mockAuthDb, mockRandom, mockClock, mockMail, &settings)
 		actual, err := underTest.SignUp(context.Background(), email, password)
 
 		require.NoError(t, err)
@@ -96,7 +97,7 @@ func TestSignUp(t *testing.T) {
 	t.Run("should return ErrAccountExists", func(t *testing.T) {
 		t.Parallel()
 
-		mockAuthDb := mocks.NewMockAuth(t)
+		mockAuthDb := mocks.NewMockDb(t)
 		mockRandom := mocks.NewMockRandom(t)
 		mockClock := mocks.NewMockClock(t)
 		mockMail := mocks.NewMockMail(t)
@@ -106,19 +107,19 @@ func TestSignUp(t *testing.T) {
 		createTime := time.Date(2020, 1, 1, 0, 0, 0, 0, time.UTC)
 		password := "SomeStrongPassword123!"
 		salt := []byte("salt")
-		user := types.NewUser(userId, email, false, nil, false, service.GetHashPassword(password, salt), salt, createTime)
+		user := auth_types.NewUser(userId, email, false, nil, false, authentication.GetHashPassword(password, salt), salt, createTime)
 
 		ctx := context.Background()
 		mockRandom.EXPECT().UUID(ctx).Return(user.Id, nil)
 		mockRandom.EXPECT().Bytes(ctx, 16).Return(salt, nil)
 		mockClock.EXPECT().Now().Return(createTime)
 
-		mockAuthDb.EXPECT().InsertUser(context.Background(), user).Return(db.ErrAlreadyExists)
+		mockAuthDb.EXPECT().InsertUser(context.Background(), user).Return(core.ErrAlreadyExists)
 
-		underTest := service.NewAuth(mockAuthDb, mockRandom, mockClock, mockMail, &settings)
+		underTest := authentication.NewService(mockAuthDb, mockRandom, mockClock, mockMail, &settings)
 
 		_, err := underTest.SignUp(context.Background(), user.Email, password)
-		assert.Equal(t, service.ErrAccountExists, err)
+		assert.Equal(t, authentication.ErrAccountExists, err)
 	})
 }
 
@@ -127,30 +128,30 @@ func TestSendVerificationMail(t *testing.T) {
 	t.Run("should use stored token and send mail", func(t *testing.T) {
 		t.Parallel()
 
-		token := types.NewToken(
+		token := auth_types.NewToken(
 			uuid.New(),
 			"sessionId",
 			"someRandomTokenToUse",
-			types.TokenTypeEmailVerify,
+			auth_types.TokenTypeEmailVerify,
 			time.Date(2020, 1, 1, 0, 0, 0, 0, time.UTC),
 			time.Date(2020, 1, 2, 0, 0, 0, 0, time.UTC))
-		tokens := []*types.Token{token}
+		tokens := []*auth_types.Token{token}
 
 		email := "some@email.de"
 		userId := uuid.New()
 
-		mockAuthDb := mocks.NewMockAuth(t)
+		mockAuthDb := mocks.NewMockDb(t)
 		mockRandom := mocks.NewMockRandom(t)
 		mockClock := mocks.NewMockClock(t)
 		mockMail := mocks.NewMockMail(t)
 
 		ctx := context.Background()
-		mockAuthDb.EXPECT().GetTokensByUserIdAndType(context.Background(), userId, types.TokenTypeEmailVerify).Return(tokens, nil)
+		mockAuthDb.EXPECT().GetTokensByUserIdAndType(context.Background(), userId, auth_types.TokenTypeEmailVerify).Return(tokens, nil)
 		mockMail.EXPECT().SendMail(ctx, email, "Welcome to spend-sparrow", mock.MatchedBy(func(message string) bool {
 			return strings.Contains(message, token.Token)
 		})).Return()
 
-		underTest := service.NewAuth(mockAuthDb, mockRandom, mockClock, mockMail, &settings)
+		underTest := authentication.NewService(mockAuthDb, mockRandom, mockClock, mockMail, &settings)
 
 		underTest.SendVerificationMail(context.Background(), userId, email)
 	})
diff --git a/test/it_test.go b/test/it_test.go
index 186ac94..9a4cf3f 100644
--- a/test/it_test.go
+++ b/test/it_test.go
@@ -7,8 +7,9 @@ import (
 	"net/http"
 	"net/url"
 	"spend-sparrow/internal"
-	"spend-sparrow/internal/service"
-	"spend-sparrow/internal/types"
+	"spend-sparrow/internal/auth_types"
+	"spend-sparrow/internal/authentication"
+	"spend-sparrow/internal/core"
 	"strconv"
 	"strings"
 	"sync/atomic"
@@ -117,7 +118,7 @@ func waitForReady(
 		default:
 			if time.Since(startTime) >= timeout {
 				t.Fatal("timeout reached while waiting for endpoint")
-				return types.ErrInternal
+				return core.ErrInternal
 			}
 			// wait a little while between checks
 			time.Sleep(250 * time.Millisecond)
@@ -178,7 +179,7 @@ func createValidUserSession(t *testing.T, db *sqlx.DB, add string) (uuid.UUID, s
 	t.Helper()
 	userId := uuid.New()
 	sessionId := "session-id" + add
-	pass := service.GetHashPassword("password", []byte("salt"))
+	pass := authentication.GetHashPassword("password", []byte("salt"))
 	csrfToken := "my-verifying-token" + add
 	email := add + "mail@mail.de"
 
@@ -193,7 +194,7 @@ func createValidUserSession(t *testing.T, db *sqlx.DB, add string) (uuid.UUID, s
 
 	_, err = db.ExecContext(context.Background(), `
 		INSERT INTO token (token, user_id, session_id, type, created_at, expires_at)
-		VALUES (?, ?, ?, ?, datetime(), datetime("now", "+1 day"))`, csrfToken, userId, sessionId, types.TokenTypeCsrf)
+		VALUES (?, ?, ?, ?, datetime(), datetime("now", "+1 day"))`, csrfToken, userId, sessionId, auth_types.TokenTypeCsrf)
 	require.NoError(t, err)
 
 	return userId, csrfToken, sessionId
diff --git a/test/main_it_test.go b/test/main_it_test.go
index c4a6b50..08ed048 100644
--- a/test/main_it_test.go
+++ b/test/main_it_test.go
@@ -3,8 +3,8 @@ package test_test
 import (
 	"net/http"
 	"net/url"
-	"spend-sparrow/internal/service"
-	"spend-sparrow/internal/types"
+	"spend-sparrow/internal/auth_types"
+	"spend-sparrow/internal/authentication"
 	"strings"
 	"testing"
 	"time"
@@ -110,7 +110,7 @@ func TestIntegrationAuth(t *testing.T) {
 
 			userId := uuid.New()
 			sessionId := "session-id"
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 
 			_, err := db.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
@@ -136,7 +136,7 @@ func TestIntegrationAuth(t *testing.T) {
 			db, basePath, ctx := setupIntegrationTest(t)
 
 			userId := uuid.New()
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 
 			_, err := db.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
@@ -163,7 +163,7 @@ func TestIntegrationAuth(t *testing.T) {
 			db, basePath, ctx := setupIntegrationTest(t)
 
 			userId := uuid.New()
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 
 			_, err := db.ExecContext(ctx, `
 				INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
@@ -206,7 +206,7 @@ func TestIntegrationAuth(t *testing.T) {
 			db, basePath, ctx := setupIntegrationTest(t)
 
 			userId := uuid.New()
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 
 			_, err := db.ExecContext(ctx, `
 				INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
@@ -247,7 +247,7 @@ func TestIntegrationAuth(t *testing.T) {
 
 			db, basePath, ctx := setupIntegrationTest(t)
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := db.ExecContext(ctx, `
 				INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 				VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, uuid.New(), pass, []byte("salt"))
@@ -295,7 +295,7 @@ func TestIntegrationAuth(t *testing.T) {
 
 			db, basePath, ctx := setupIntegrationTest(t)
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := db.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 			VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, uuid.New(), pass, []byte("salt"))
@@ -414,7 +414,7 @@ func TestIntegrationAuth(t *testing.T) {
 
 			db, basePath, ctx := setupIntegrationTest(t)
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := db.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 			VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, uuid.New(), pass, []byte("salt"))
@@ -467,7 +467,7 @@ func TestIntegrationAuth(t *testing.T) {
 
 			userId := uuid.New()
 			sessionId := "session-id"
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 
 			_, err := db.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
@@ -550,7 +550,7 @@ func TestIntegrationAuth(t *testing.T) {
 
 			_, err := db.ExecContext(ctx, `
 				INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at)
-				VALUES (?, "mail@mail.de", TRUE, FALSE, ?, ?, datetime())`, uuid.New(), service.GetHashPassword("password", []byte("salt")), []byte("salt"))
+				VALUES (?, "mail@mail.de", TRUE, FALSE, ?, ?, datetime())`, uuid.New(), authentication.GetHashPassword("password", []byte("salt")), []byte("salt"))
 			require.NoError(t, err)
 
 			req, err := http.NewRequestWithContext(ctx, http.MethodGet, basePath+"/auth/signup", nil)
@@ -631,7 +631,7 @@ func TestIntegrationAuth(t *testing.T) {
 			require.NoError(t, err)
 			assert.Equal(t, 1, rows)
 			var token string
-			err = db.QueryRowContext(ctx, "SELECT t.token FROM token t INNER JOIN user u ON u.user_id = t.user_id WHERE u.email = ? AND t.type = ?", "mail@mail.de", types.TokenTypeEmailVerify).Scan(&token)
+			err = db.QueryRowContext(ctx, "SELECT t.token FROM token t INNER JOIN user u ON u.user_id = t.user_id WHERE u.email = ? AND t.type = ?", "mail@mail.de", auth_types.TokenTypeEmailVerify).Scan(&token)
 			require.NoError(t, err)
 			assert.NotEmpty(t, token)
 		})
@@ -676,7 +676,7 @@ func TestIntegrationAuth(t *testing.T) {
 			require.NoError(t, err)
 			_, err = db.ExecContext(ctx, `
 				INSERT INTO token (token, user_id, type, created_at, expires_at)
-				VALUES (?, ?, ?, datetime("now", "-16 minute"), datetime("now", "-1 minute"))`, token, userId, types.TokenTypeEmailVerify)
+				VALUES (?, ?, ?, datetime("now", "-16 minute"), datetime("now", "-1 minute"))`, token, userId, auth_types.TokenTypeEmailVerify)
 			require.NoError(t, err)
 
 			req, err := http.NewRequestWithContext(ctx, http.MethodGet, basePath+"/auth/verify-email?token="+token, nil)
@@ -706,7 +706,7 @@ func TestIntegrationAuth(t *testing.T) {
 			require.NoError(t, err)
 			_, err = db.ExecContext(ctx, `
 				INSERT INTO token (token, user_id, session_id, type, created_at, expires_at)
-				VALUES (?, ?, "", ?, datetime("now"), datetime("now", "+15 minute"))`, token, userId, types.TokenTypeEmailVerify)
+				VALUES (?, ?, "", ?, datetime("now"), datetime("now", "+15 minute"))`, token, userId, auth_types.TokenTypeEmailVerify)
 			require.NoError(t, err)
 
 			req, err := http.NewRequestWithContext(ctx, http.MethodGet, basePath+"/auth/verify-email?token="+token, nil)
@@ -746,7 +746,7 @@ func TestIntegrationAuth(t *testing.T) {
 			userId := uuid.New()
 			sessionId := "session-id"
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := db.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 			VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, userId, pass, []byte("salt"))
@@ -765,7 +765,7 @@ func TestIntegrationAuth(t *testing.T) {
 			assert.Equal(t, http.StatusOK, resp.StatusCode)
 
 			var csrfToken string
-			err = db.QueryRowContext(ctx, "SELECT token FROM token WHERE user_id = ? AND type = ?", userId, types.TokenTypeCsrf).Scan(&csrfToken)
+			err = db.QueryRowContext(ctx, "SELECT token FROM token WHERE user_id = ? AND type = ?", userId, auth_types.TokenTypeCsrf).Scan(&csrfToken)
 			require.NoError(t, err)
 
 			req, err = http.NewRequestWithContext(ctx, http.MethodPost, basePath+"/api/auth/signout", nil)
@@ -824,7 +824,7 @@ func TestIntegrationAuth(t *testing.T) {
 			db, basePath, ctx := setupIntegrationTest(t)
 			userId := uuid.New()
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := db.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 			VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, userId, pass, []byte("salt"))
@@ -870,7 +870,7 @@ func TestIntegrationAuth(t *testing.T) {
 			db, basePath, ctx := setupIntegrationTest(t)
 			userId := uuid.New()
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := db.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 			VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, userId, pass, []byte("salt"))
@@ -1039,7 +1039,7 @@ func TestIntegrationAuth(t *testing.T) {
 			db, basePath, ctx := setupIntegrationTest(t)
 			userId := uuid.New()
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := db.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 			VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, userId, pass, []byte("salt"))
@@ -1078,7 +1078,7 @@ func TestIntegrationAuth(t *testing.T) {
 
 			db, basePath, ctx := setupIntegrationTest(t)
 			userId := uuid.New()
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 
 			_, err := db.ExecContext(ctx, `
 				INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
@@ -1128,7 +1128,7 @@ func TestIntegrationAuth(t *testing.T) {
 
 			db, basePath, ctx := setupIntegrationTest(t)
 			userId := uuid.New()
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 
 			_, err := db.ExecContext(ctx, `
 				INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
@@ -1180,7 +1180,7 @@ func TestIntegrationAuth(t *testing.T) {
 			userId := uuid.New()
 			userIdOther := uuid.New()
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := db.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 			VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, userId, pass, []byte("salt"))
@@ -1230,7 +1230,7 @@ func TestIntegrationAuth(t *testing.T) {
 
 			assert.Equal(t, http.StatusOK, resp.StatusCode)
 
-			pass = service.GetHashPassword("MyNewSecurePassword1!", []byte("salt"))
+			pass = authentication.GetHashPassword("MyNewSecurePassword1!", []byte("salt"))
 			var rows int
 			err = db.QueryRowContext(ctx, "SELECT COUNT(*) FROM user WHERE user_id = ? AND password = ?", userId, pass).Scan(&rows)
 			require.NoError(t, err)
@@ -1259,7 +1259,7 @@ func TestIntegrationAuth(t *testing.T) {
 			d, basePath, ctx := setupIntegrationTest(t)
 			userId := uuid.New()
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := d.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 			VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, userId, pass, []byte("salt"))
@@ -1287,7 +1287,7 @@ func TestIntegrationAuth(t *testing.T) {
 			d, basePath, ctx := setupIntegrationTest(t)
 			userId := uuid.New()
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := d.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 			VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, userId, pass, []byte("salt"))
@@ -1317,7 +1317,7 @@ func TestIntegrationAuth(t *testing.T) {
 			assert.Equal(t, http.StatusBadRequest, resp.StatusCode)
 
 			var rows int
-			err = d.QueryRowContext(ctx, "SELECT COUNT(*) FROM token WHERE user_id = ? AND type = ?", userId, types.TokenTypePasswordReset).Scan(&rows)
+			err = d.QueryRowContext(ctx, "SELECT COUNT(*) FROM token WHERE user_id = ? AND type = ?", userId, auth_types.TokenTypePasswordReset).Scan(&rows)
 			require.NoError(t, err)
 			assert.Equal(t, 0, rows)
 		})
@@ -1362,7 +1362,7 @@ func TestIntegrationAuth(t *testing.T) {
 			db, basePath, ctx := setupIntegrationTest(t)
 
 			userId := uuid.New()
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := db.ExecContext(ctx, `
 				INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at)
 				VALUES (?, "mail@mail.de", TRUE, FALSE, ?, ?, datetime())`, userId, pass, []byte("salt"))
@@ -1399,7 +1399,7 @@ func TestIntegrationAuth(t *testing.T) {
 			assert.Contains(t, resp.Header.Get("Hx-Trigger"), msg)
 
 			var rows int
-			err = db.QueryRowContext(ctx, "SELECT COUNT(*) FROM token WHERE user_id = ? AND type = ?", userId, types.TokenTypePasswordReset).Scan(&rows)
+			err = db.QueryRowContext(ctx, "SELECT COUNT(*) FROM token WHERE user_id = ? AND type = ?", userId, auth_types.TokenTypePasswordReset).Scan(&rows)
 			require.NoError(t, err)
 			assert.Equal(t, 1, rows)
 		})
@@ -1412,7 +1412,7 @@ func TestIntegrationAuth(t *testing.T) {
 			d, basePath, ctx := setupIntegrationTest(t)
 			userId := uuid.New()
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := d.ExecContext(ctx, `
 				INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 				VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, userId, pass, []byte("salt"))
@@ -1455,7 +1455,7 @@ func TestIntegrationAuth(t *testing.T) {
 			d, basePath, ctx := setupIntegrationTest(t)
 			userId := uuid.New()
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := d.ExecContext(ctx, `
 				INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 				VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, userId, pass, []byte("salt"))
@@ -1475,7 +1475,7 @@ func TestIntegrationAuth(t *testing.T) {
 			token := "password-reset-token"
 			_, err = d.ExecContext(ctx, `
 				INSERT INTO token (token, user_id, session_id, type, created_at, expires_at)
-				VALUES (?, ?, ?, ?, datetime("now", "-16 minute"), datetime("now", "-1 minute"))`, token, userId, "", types.TokenTypePasswordReset)
+				VALUES (?, ?, ?, ?, datetime("now", "-16 minute"), datetime("now", "-1 minute"))`, token, userId, "", auth_types.TokenTypePasswordReset)
 			require.NoError(t, err)
 
 			formData := url.Values{
@@ -1504,7 +1504,7 @@ func TestIntegrationAuth(t *testing.T) {
 			d, basePath, ctx := setupIntegrationTest(t)
 			userId := uuid.New()
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := d.ExecContext(ctx, `
 				INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 				VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, userId, pass, []byte("salt"))
@@ -1524,7 +1524,7 @@ func TestIntegrationAuth(t *testing.T) {
 			token := "password-reset-token"
 			_, err = d.ExecContext(ctx, `
 				INSERT INTO token (token, user_id, session_id, type, created_at, expires_at)
-				VALUES (?, ?, ?, ?, datetime("now"), datetime("now", "+15 minute"))`, token, userId, "", types.TokenTypePasswordReset)
+				VALUES (?, ?, ?, ?, datetime("now"), datetime("now", "+15 minute"))`, token, userId, "", auth_types.TokenTypePasswordReset)
 			require.NoError(t, err)
 
 			formData := url.Values{
@@ -1553,7 +1553,7 @@ func TestIntegrationAuth(t *testing.T) {
 			d, basePath, ctx := setupIntegrationTest(t)
 			userId := uuid.New()
 
-			pass := service.GetHashPassword("password", []byte("salt"))
+			pass := authentication.GetHashPassword("password", []byte("salt"))
 			_, err := d.ExecContext(ctx, `
 			INSERT INTO user (user_id, email, email_verified, is_admin, password, salt, created_at) 
 			VALUES (?, "mail@mail.de", FALSE, FALSE, ?, ?, datetime())`, userId, pass, []byte("salt"))
@@ -1590,7 +1590,7 @@ func TestIntegrationAuth(t *testing.T) {
 			assert.Equal(t, http.StatusOK, resp.StatusCode)
 
 			var token string
-			err = d.QueryRowContext(ctx, "SELECT token FROM token WHERE type = ?", types.TokenTypePasswordReset).Scan(&token)
+			err = d.QueryRowContext(ctx, "SELECT token FROM token WHERE type = ?", auth_types.TokenTypePasswordReset).Scan(&token)
 			require.NoError(t, err)
 
 			formData = url.Values{