diff --git a/README.md b/README.md
index e8acfba..c0c9f05 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,122 @@
-# FastAPI Application
+# User Authentication Service
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A professional and reliable user authentication service built with FastAPI and SQLite. This service provides a secure authentication flow with JWT tokens, including refresh token functionality.
+
+## Features
+
+- User registration and login
+- JWT-based authentication with access and refresh tokens
+- Password hashing with bcrypt
+- User profile management
+- Role-based access control (superuser and regular user)
+- Health check endpoint
+- Alembic migrations
+- SQLite database
+
+## Project Structure
+
+```
+.
+├── alembic.ini
+├── app
+│   ├── api
+│   │   ├── deps.py
+│   │   ├── endpoints
+│   │   │   ├── auth.py
+│   │   │   └── users.py
+│   │   └── api.py
+│   ├── core
+│   │   ├── config.py
+│   │   └── security.py
+│   ├── db
+│   │   ├── base.py
+│   │   ├── base_class.py
+│   │   └── session.py
+│   ├── models
+│   │   └── user.py
+│   ├── schemas
+│   │   ├── token.py
+│   │   └── user.py
+│   ├── services
+│   │   └── user.py
+│   └── storage
+│       └── db
+├── main.py
+├── migrations
+│   ├── env.py
+│   ├── README
+│   ├── script.py.mako
+│   └── versions
+│       └── 001_create_user_table.py
+└── requirements.txt
+```
+
+## Getting Started
+
+### Prerequisites
+
+- Python 3.8 or higher
+
+### Installation
+
+1. Clone the repository
+```bash
+git clone <repository-url>
+cd userauthenticationservice
+```
+
+2. Install dependencies
+```bash
+pip install -r requirements.txt
+```
+
+3. Run the migrations
+```bash
+alembic upgrade head
+```
+
+4. Start the server
+```bash
+uvicorn main:app --reload
+```
+
+## API Documentation
+
+Once the server is running, you can access the API documentation at:
+
+- Swagger UI: http://localhost:8000/docs
+- ReDoc: http://localhost:8000/redoc
+
+## API Endpoints
+
+### Authentication
+
+- `POST /api/v1/auth/register` - Register a new user
+- `POST /api/v1/auth/login` - Login and get tokens
+- `POST /api/v1/auth/refresh-token` - Refresh access token
+
+### Users
+
+- `GET /api/v1/users/me` - Get current user profile
+- `PUT /api/v1/users/me` - Update current user profile
+- `GET /api/v1/users/{user_id}` - Get user by ID (superuser only)
+
+### Health Check
+
+- `GET /health` - Service health check
+
+## Security
+
+- Passwords are hashed using bcrypt
+- Authentication is handled via JWT tokens
+- Access tokens expire after 30 minutes
+- Refresh tokens expire after 7 days
+- CORS protection is enabled
+
+## Development
+
+For development, you can run the server with auto-reload:
+
+```bash
+uvicorn main:app --reload
+```
\ No newline at end of file
diff --git a/alembic.ini b/alembic.ini
new file mode 100644
index 0000000..9009f5b
--- /dev/null
+++ b/alembic.ini
@@ -0,0 +1,111 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = migrations
+
+# template used to generate migration file names; The default value is %%(rev)s_%%(slug)s
+# Uncomment the line below if you want the files to be prepended with date and time
+# see https://alembic.sqlalchemy.org/en/latest/tutorial.html#editing-the-ini-file
+# for all available tokens
+# file_template = %%(year)d_%%(month).2d_%%(day).2d_%%(hour).2d%%(minute).2d-%%(rev)s_%%(slug)s
+
+# sys.path path, will be prepended to sys.path if present.
+# defaults to the current working directory.
+prepend_sys_path = .
+
+# timezone to use when rendering the date within the migration file
+# as well as the filename.
+# If specified, requires the python-dateutil library that can be
+# installed by adding `alembic[tz]` to the pip requirements
+# string value is passed to dateutil.tz.gettz()
+# leave blank for localtime
+# timezone =
+
+# max length of characters to apply to the
+# "slug" field
+# truncate_slug_length = 40
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+# set to 'true' to allow .pyc and .pyo files without
+# a source .py file to be detected as revisions in the
+# versions/ directory
+# sourceless = false
+
+# version location specification; This defaults
+# to migrations/versions.  When using multiple version
+# directories, initial revisions must be specified with --version-path.
+# The path separator used here should be the separator specified by "version_path_separator" below.
+# version_locations = %(here)s/bar:%(here)s/bat:migrations/versions
+
+# version path separator; As mentioned above, this is the character used to split
+# version_locations. The default within new alembic.ini files is "os", which uses os.pathsep.
+# If this key is omitted entirely, it falls back to the legacy behavior of splitting on spaces and/or commas.
+# Valid values for version_path_separator are:
+#
+# version_path_separator = :
+# version_path_separator = ;
+# version_path_separator = space
+version_path_separator = os  # Use os.pathsep. Default configuration used for new projects.
+
+# set to 'true' to search source files recursively
+# in each "version_locations" directory
+# new in Alembic version 1.10
+# recursive_version_locations = false
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+# SQLite URL example - make sure to use an absolute path for the database file
+sqlalchemy.url = sqlite:////app/storage/db/db.sqlite
+
+
+[post_write_hooks]
+# post_write_hooks defines scripts or Python functions that are run
+# on newly generated revision scripts.  See the documentation for further
+# detail and examples
+
+# format using "black" - use the console_scripts runner, against the "black" entrypoint
+# hooks = black
+# black.type = console_scripts
+# black.entrypoint = black
+# black.options = -l 79 REVISION_SCRIPT_FILENAME
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S
\ No newline at end of file
diff --git a/app/__init__.py b/app/__init__.py
new file mode 100644
index 0000000..b96d27b
--- /dev/null
+++ b/app/__init__.py
@@ -0,0 +1 @@
+# Make app directory a package
diff --git a/app/api/__init__.py b/app/api/__init__.py
new file mode 100644
index 0000000..02057e7
--- /dev/null
+++ b/app/api/__init__.py
@@ -0,0 +1 @@
+# Make api directory a package
diff --git a/app/api/api.py b/app/api/api.py
new file mode 100644
index 0000000..5a94834
--- /dev/null
+++ b/app/api/api.py
@@ -0,0 +1,7 @@
+from fastapi import APIRouter
+
+from app.api.endpoints import auth, users
+
+api_router = APIRouter()
+api_router.include_router(auth.router, prefix="/auth", tags=["Authentication"])
+api_router.include_router(users.router, prefix="/users", tags=["Users"])
diff --git a/app/api/deps.py b/app/api/deps.py
new file mode 100644
index 0000000..d10b917
--- /dev/null
+++ b/app/api/deps.py
@@ -0,0 +1,70 @@
+
+from fastapi import Depends, HTTPException, status
+from fastapi.security import OAuth2PasswordBearer
+from jose import jwt
+from pydantic import ValidationError
+from sqlalchemy.orm import Session
+
+from app import schemas
+from app.core.config import settings
+from app.db.session import get_db
+from app.models.user import User
+from app.services import user as user_service
+
+oauth2_scheme = OAuth2PasswordBearer(tokenUrl=f"{settings.API_V1_STR}/auth/login")
+
+
+def get_current_user(
+    db: Session = Depends(get_db),
+    token: str = Depends(oauth2_scheme),
+) -> User:
+    """
+    Get the current user from the token.
+    """
+    try:
+        payload = jwt.decode(
+            token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
+        )
+        token_data = schemas.TokenPayload(**payload)
+    except (jwt.JWTError, ValidationError):
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="Could not validate credentials",
+        )
+
+    # Get the user from the token
+    user = user_service.get_by_id(db, id=int(token_data.sub))
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="User not found",
+        )
+    return user
+
+
+def get_current_active_user(
+    current_user: User = Depends(get_current_user),
+) -> User:
+    """
+    Get the current active user.
+    """
+    if not user_service.is_active(current_user):
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Inactive user",
+        )
+    return current_user
+
+
+def get_current_active_superuser(
+    current_user: User = Depends(get_current_active_user),
+) -> User:
+    """
+    Get the current active superuser.
+    """
+    if not user_service.is_superuser(current_user):
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="The user doesn't have enough privileges",
+        )
+    return current_user
diff --git a/app/api/endpoints/__init__.py b/app/api/endpoints/__init__.py
new file mode 100644
index 0000000..8d04f8f
--- /dev/null
+++ b/app/api/endpoints/__init__.py
@@ -0,0 +1 @@
+# Make endpoints directory a package
diff --git a/app/api/endpoints/auth.py b/app/api/endpoints/auth.py
new file mode 100644
index 0000000..0ac653f
--- /dev/null
+++ b/app/api/endpoints/auth.py
@@ -0,0 +1,146 @@
+from datetime import timedelta
+from typing import Any
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from fastapi.security import OAuth2PasswordRequestForm
+from jose import jwt
+from pydantic import ValidationError
+from sqlalchemy.orm import Session
+
+from app import schemas
+from app.api import deps
+from app.core import security
+from app.core.config import settings
+from app.services import user as user_service
+
+router = APIRouter()
+
+
+@router.post("/register", response_model=schemas.User)
+def register(
+    *,
+    db: Session = Depends(deps.get_db),
+    user_in: schemas.UserCreate,
+) -> Any:
+    """
+    Register a new user.
+    """
+    # Check if user with email exists
+    user = user_service.get_by_email(db, email=user_in.email)
+    if user:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Email already registered",
+        )
+
+    # Check if user with username exists
+    user = user_service.get_by_username(db, username=user_in.username)
+    if user:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Username already taken",
+        )
+
+    # Create new user
+    user = user_service.create(db, obj_in=user_in)
+    return user
+
+
+@router.post("/login", response_model=schemas.Token)
+def login(
+    db: Session = Depends(deps.get_db),
+    form_data: OAuth2PasswordRequestForm = Depends(),
+) -> Any:
+    """
+    Login for access token.
+    """
+    # Authenticate user
+    user = user_service.authenticate(
+        db, email_or_username=form_data.username, password=form_data.password
+    )
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Incorrect email/username or password",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+
+    # Check if user is active
+    if not user_service.is_active(user):
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Inactive user",
+        )
+
+    # Create access token
+    access_token_expires = timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
+    access_token = security.create_access_token(
+        user.id, expires_delta=access_token_expires
+    )
+
+    # Create refresh token
+    refresh_token = security.create_refresh_token(user.id)
+
+    return {
+        "access_token": access_token,
+        "refresh_token": refresh_token,
+        "token_type": "bearer",
+    }
+
+
+@router.post("/refresh-token", response_model=schemas.Token)
+def refresh_token(
+    db: Session = Depends(deps.get_db),
+    token_data: schemas.RefreshToken = None,
+) -> Any:
+    """
+    Refresh access token.
+    """
+    try:
+        # Decode the refresh token
+        payload = jwt.decode(
+            token_data.refresh_token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
+        )
+        token_data = schemas.TokenPayload(**payload)
+
+        # Check if token type is refresh
+        if payload.get("type") != "refresh":
+            raise HTTPException(
+                status_code=status.HTTP_400_BAD_REQUEST,
+                detail="Invalid refresh token",
+            )
+    except (jwt.JWTError, ValidationError):
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="Could not validate credentials",
+        )
+
+    # Get the user from the token
+    user = user_service.get_by_id(db, id=int(token_data.sub))
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="User not found",
+        )
+
+    # Check if user is active
+    if not user_service.is_active(user):
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Inactive user",
+        )
+
+    # Create new access token
+    access_token_expires = timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
+    access_token = security.create_access_token(
+        user.id, expires_delta=access_token_expires
+    )
+
+    # Create new refresh token
+    refresh_token = security.create_refresh_token(user.id)
+
+    return {
+        "access_token": access_token,
+        "refresh_token": refresh_token,
+        "token_type": "bearer",
+    }
diff --git a/app/api/endpoints/users.py b/app/api/endpoints/users.py
new file mode 100644
index 0000000..6f2ddc6
--- /dev/null
+++ b/app/api/endpoints/users.py
@@ -0,0 +1,64 @@
+from typing import Any
+
+from fastapi import APIRouter, Body, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app import schemas
+from app.api import deps
+from app.models.user import User
+from app.services import user as user_service
+
+router = APIRouter()
+
+
+@router.get("/me", response_model=schemas.User)
+def read_user_me(
+    current_user: User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get current user.
+    """
+    return current_user
+
+
+@router.put("/me", response_model=schemas.User)
+def update_user_me(
+    *,
+    db: Session = Depends(deps.get_db),
+    full_name: str = Body(None),
+    password: str = Body(None),
+    current_user: User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Update current user.
+    """
+    current_user_data = schemas.UserUpdate(
+        full_name=full_name or current_user.full_name,
+        password=password,
+    )
+    user = user_service.update(db, db_obj=current_user, obj_in=current_user_data)
+    return user
+
+
+@router.get("/{user_id}", response_model=schemas.User)
+def read_user_by_id(
+    user_id: int,
+    current_user: User = Depends(deps.get_current_active_user),
+    db: Session = Depends(deps.get_db),
+) -> Any:
+    """
+    Get a specific user by id.
+    """
+    user = user_service.get_by_id(db, id=user_id)
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="User not found",
+        )
+    # Only allow superusers to access other users' data
+    if user.id != current_user.id and not user_service.is_superuser(current_user):
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="Not enough permissions",
+        )
+    return user
diff --git a/app/core/__init__.py b/app/core/__init__.py
new file mode 100644
index 0000000..4fb144c
--- /dev/null
+++ b/app/core/__init__.py
@@ -0,0 +1 @@
+# Make core directory a package
diff --git a/app/core/config.py b/app/core/config.py
new file mode 100644
index 0000000..af662b0
--- /dev/null
+++ b/app/core/config.py
@@ -0,0 +1,41 @@
+from pathlib import Path
+from typing import List, Union
+
+from pydantic import AnyHttpUrl, validator
+from pydantic_settings import BaseSettings
+
+
+class Settings(BaseSettings):
+    PROJECT_NAME: str = "User Authentication Service"
+    VERSION: str = "0.1.0"
+    API_V1_STR: str = "/api/v1"
+
+    # SECURITY
+    SECRET_KEY: str = "your-secret-key-change-in-production"  # Change in production!
+    ACCESS_TOKEN_EXPIRE_MINUTES: int = 30  # 30 minutes
+    REFRESH_TOKEN_EXPIRE_DAYS: int = 7  # 7 days
+    ALGORITHM: str = "HS256"
+
+    # CORS
+    BACKEND_CORS_ORIGINS: List[AnyHttpUrl] = []
+
+    @validator("BACKEND_CORS_ORIGINS", pre=True)
+    def assemble_cors_origins(cls, v: Union[str, List[str]]) -> Union[List[str], str]:
+        if isinstance(v, str) and not v.startswith("["):
+            return [i.strip() for i in v.split(",")]
+        elif isinstance(v, (list, str)):
+            return v
+        raise ValueError(v)
+
+    # DB
+    DB_DIR: Path = Path("/app") / "storage" / "db"
+    SQLALCHEMY_DATABASE_URL: str = f"sqlite:///{DB_DIR}/db.sqlite"
+
+    class Config:
+        case_sensitive = True
+
+
+settings = Settings()
+
+# Ensure DB directory exists
+settings.DB_DIR.mkdir(parents=True, exist_ok=True)
diff --git a/app/core/security.py b/app/core/security.py
new file mode 100644
index 0000000..2be4eda
--- /dev/null
+++ b/app/core/security.py
@@ -0,0 +1,48 @@
+from datetime import datetime, timedelta
+from typing import Any, Union
+
+from jose import jwt
+from passlib.context import CryptContext
+
+from app.core.config import settings
+
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+
+def create_access_token(subject: Union[str, Any], expires_delta: timedelta = None) -> str:
+    """
+    Create a JWT access token.
+    """
+    if expires_delta:
+        expire = datetime.utcnow() + expires_delta
+    else:
+        expire = datetime.utcnow() + timedelta(
+            minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES
+        )
+    to_encode = {"exp": expire, "sub": str(subject)}
+    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
+    return encoded_jwt
+
+
+def create_refresh_token(subject: Union[str, Any]) -> str:
+    """
+    Create a JWT refresh token.
+    """
+    expire = datetime.utcnow() + timedelta(days=settings.REFRESH_TOKEN_EXPIRE_DAYS)
+    to_encode = {"exp": expire, "sub": str(subject), "type": "refresh"}
+    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
+    return encoded_jwt
+
+
+def verify_password(plain_password: str, hashed_password: str) -> bool:
+    """
+    Verify a password against a hash.
+    """
+    return pwd_context.verify(plain_password, hashed_password)
+
+
+def get_password_hash(password: str) -> str:
+    """
+    Generate a hash for a password.
+    """
+    return pwd_context.hash(password)
diff --git a/app/db/__init__.py b/app/db/__init__.py
new file mode 100644
index 0000000..852948e
--- /dev/null
+++ b/app/db/__init__.py
@@ -0,0 +1 @@
+# Make db directory a package
diff --git a/app/db/base.py b/app/db/base.py
new file mode 100644
index 0000000..f002e1b
--- /dev/null
+++ b/app/db/base.py
@@ -0,0 +1,4 @@
+# Import all the models, so that Base has them before being
+# imported by Alembic
+from app.db.base_class import Base  # noqa
+from app.models.user import User  # noqa
\ No newline at end of file
diff --git a/app/db/base_class.py b/app/db/base_class.py
new file mode 100644
index 0000000..1e2aabe
--- /dev/null
+++ b/app/db/base_class.py
@@ -0,0 +1,14 @@
+from typing import Any
+
+from sqlalchemy.ext.declarative import as_declarative, declared_attr
+
+
+@as_declarative()
+class Base:
+    id: Any
+    __name__: str
+
+    # Generate __tablename__ automatically
+    @declared_attr
+    def __tablename__(cls) -> str:
+        return cls.__name__.lower()
diff --git a/app/db/session.py b/app/db/session.py
new file mode 100644
index 0000000..fe53228
--- /dev/null
+++ b/app/db/session.py
@@ -0,0 +1,19 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+from app.core.config import settings
+
+engine = create_engine(
+    settings.SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False}  # Needed for SQLite
+)
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+
+# Dependency to get DB session
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
diff --git a/app/models/__init__.py b/app/models/__init__.py
new file mode 100644
index 0000000..f4efafc
--- /dev/null
+++ b/app/models/__init__.py
@@ -0,0 +1 @@
+# Make models directory a package
diff --git a/app/models/user.py b/app/models/user.py
new file mode 100644
index 0000000..33b67a5
--- /dev/null
+++ b/app/models/user.py
@@ -0,0 +1,16 @@
+from sqlalchemy import Boolean, Column, DateTime, Integer, String
+from sqlalchemy.sql import func
+
+from app.db.base_class import Base
+
+
+class User(Base):
+    id = Column(Integer, primary_key=True, index=True)
+    email = Column(String, unique=True, index=True, nullable=False)
+    username = Column(String, unique=True, index=True, nullable=False)
+    hashed_password = Column(String, nullable=False)
+    full_name = Column(String, nullable=True)
+    is_active = Column(Boolean, default=True)
+    is_superuser = Column(Boolean, default=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
diff --git a/app/schemas/__init__.py b/app/schemas/__init__.py
new file mode 100644
index 0000000..efd6ed0
--- /dev/null
+++ b/app/schemas/__init__.py
@@ -0,0 +1,8 @@
+# Re-export schemas for easier imports
+from app.schemas.token import RefreshToken, Token, TokenPayload
+from app.schemas.user import User, UserCreate, UserInDB, UserInDBBase, UserUpdate
+
+__all__ = [
+    "Token", "TokenPayload", "RefreshToken",
+    "User", "UserCreate", "UserUpdate", "UserInDB", "UserInDBBase",
+]
diff --git a/app/schemas/token.py b/app/schemas/token.py
new file mode 100644
index 0000000..7094682
--- /dev/null
+++ b/app/schemas/token.py
@@ -0,0 +1,18 @@
+from typing import Optional
+
+from pydantic import BaseModel
+
+
+class Token(BaseModel):
+    access_token: str
+    refresh_token: str
+    token_type: str
+
+
+class TokenPayload(BaseModel):
+    sub: Optional[str] = None
+    exp: Optional[int] = None
+
+
+class RefreshToken(BaseModel):
+    refresh_token: str
diff --git a/app/schemas/user.py b/app/schemas/user.py
new file mode 100644
index 0000000..4b53231
--- /dev/null
+++ b/app/schemas/user.py
@@ -0,0 +1,44 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel, ConfigDict, EmailStr, Field
+
+
+# Shared properties
+class UserBase(BaseModel):
+    email: Optional[EmailStr] = None
+    username: Optional[str] = None
+    is_active: Optional[bool] = True
+    is_superuser: bool = False
+    full_name: Optional[str] = None
+
+
+# Properties to receive via API on creation
+class UserCreate(UserBase):
+    email: EmailStr
+    username: str = Field(..., min_length=3, max_length=50)
+    password: str = Field(..., min_length=8)
+
+
+# Properties to receive via API on update
+class UserUpdate(UserBase):
+    password: Optional[str] = Field(None, min_length=8)
+
+
+# Properties shared by models stored in DB
+class UserInDBBase(UserBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    model_config = ConfigDict(from_attributes=True)
+
+
+# Properties to return via API
+class User(UserInDBBase):
+    pass
+
+
+# Properties stored in DB
+class UserInDB(UserInDBBase):
+    hashed_password: str
diff --git a/app/services/__init__.py b/app/services/__init__.py
new file mode 100644
index 0000000..3273d84
--- /dev/null
+++ b/app/services/__init__.py
@@ -0,0 +1 @@
+# Make services directory a package
diff --git a/app/services/user.py b/app/services/user.py
new file mode 100644
index 0000000..2b6ca4d
--- /dev/null
+++ b/app/services/user.py
@@ -0,0 +1,96 @@
+from typing import Any, Dict, Optional, Union
+
+from sqlalchemy.orm import Session
+
+from app.core.security import get_password_hash, verify_password
+from app.models.user import User
+from app.schemas.user import UserCreate, UserUpdate
+
+
+def get_by_email(db: Session, email: str) -> Optional[User]:
+    """
+    Get a user by email.
+    """
+    return db.query(User).filter(User.email == email).first()
+
+
+def get_by_username(db: Session, username: str) -> Optional[User]:
+    """
+    Get a user by username.
+    """
+    return db.query(User).filter(User.username == username).first()
+
+
+def get_by_id(db: Session, id: int) -> Optional[User]:
+    """
+    Get a user by ID.
+    """
+    return db.query(User).filter(User.id == id).first()
+
+
+def create(db: Session, *, obj_in: UserCreate) -> User:
+    """
+    Create a new user.
+    """
+    db_obj = User(
+        email=obj_in.email,
+        username=obj_in.username,
+        hashed_password=get_password_hash(obj_in.password),
+        full_name=obj_in.full_name,
+        is_superuser=obj_in.is_superuser,
+    )
+    db.add(db_obj)
+    db.commit()
+    db.refresh(db_obj)
+    return db_obj
+
+
+def update(
+    db: Session, *, db_obj: User, obj_in: Union[UserUpdate, Dict[str, Any]]
+) -> User:
+    """
+    Update a user.
+    """
+    if isinstance(obj_in, dict):
+        update_data = obj_in
+    else:
+        update_data = obj_in.model_dump(exclude_unset=True)
+    if "password" in update_data and update_data["password"]:
+        hashed_password = get_password_hash(update_data["password"])
+        del update_data["password"]
+        update_data["hashed_password"] = hashed_password
+    for field in update_data:
+        setattr(db_obj, field, update_data[field])
+    db.add(db_obj)
+    db.commit()
+    db.refresh(db_obj)
+    return db_obj
+
+
+def authenticate(db: Session, *, email_or_username: str, password: str) -> Optional[User]:
+    """
+    Authenticate a user.
+    """
+    user = get_by_email(db, email=email_or_username)
+    if not user:
+        # Try with username
+        user = get_by_username(db, username=email_or_username)
+    if not user:
+        return None
+    if not verify_password(password, user.hashed_password):
+        return None
+    return user
+
+
+def is_active(user: User) -> bool:
+    """
+    Check if a user is active.
+    """
+    return user.is_active
+
+
+def is_superuser(user: User) -> bool:
+    """
+    Check if a user is a superuser.
+    """
+    return user.is_superuser
diff --git a/main.py b/main.py
new file mode 100644
index 0000000..747ed59
--- /dev/null
+++ b/main.py
@@ -0,0 +1,39 @@
+import uvicorn
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.api import api_router
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    version=settings.VERSION,
+    description="User Authentication Service API",
+    openapi_url=f"{settings.API_V1_STR}/openapi.json",
+    docs_url="/docs",
+    redoc_url="/redoc",
+)
+
+# Set all CORS enabled origins
+if settings.BACKEND_CORS_ORIGINS:
+    app.add_middleware(
+        CORSMiddleware,
+        allow_origins=[str(origin) for origin in settings.BACKEND_CORS_ORIGINS],
+        allow_credentials=True,
+        allow_methods=["*"],
+        allow_headers=["*"],
+    )
+
+app.include_router(api_router, prefix=settings.API_V1_STR)
+
+
+@app.get("/health", tags=["Health"])
+async def health_check():
+    """
+    Health check endpoint to verify the service is running.
+    """
+    return {"status": "healthy"}
+
+
+if __name__ == "__main__":
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)
diff --git a/migrations/README b/migrations/README
new file mode 100644
index 0000000..3542e0e
--- /dev/null
+++ b/migrations/README
@@ -0,0 +1 @@
+Generic single-database configuration with SQLite.
\ No newline at end of file
diff --git a/migrations/env.py b/migrations/env.py
new file mode 100644
index 0000000..faeb1a0
--- /dev/null
+++ b/migrations/env.py
@@ -0,0 +1,78 @@
+from logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+from app.db.base import Base  # noqa
+target_metadata = Base.metadata
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+
+def run_migrations_offline() -> None:
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section, {}),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        is_sqlite = connection.dialect.name == 'sqlite'
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            render_as_batch=is_sqlite,  # Key configuration for SQLite
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()
diff --git a/migrations/script.py.mako b/migrations/script.py.mako
new file mode 100644
index 0000000..37d0cac
--- /dev/null
+++ b/migrations/script.py.mako
@@ -0,0 +1,24 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+branch_labels = ${repr(branch_labels)}
+depends_on = ${repr(depends_on)}
+
+
+def upgrade() -> None:
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    ${downgrades if downgrades else "pass"}
\ No newline at end of file
diff --git a/migrations/versions/001_create_user_table.py b/migrations/versions/001_create_user_table.py
new file mode 100644
index 0000000..7e1a076
--- /dev/null
+++ b/migrations/versions/001_create_user_table.py
@@ -0,0 +1,42 @@
+"""create user table
+
+Revision ID: 001
+Revises:
+Create Date: 2023-11-14
+
+"""
+import sqlalchemy as sa
+from alembic import op
+from sqlalchemy.sql import func
+
+# revision identifiers, used by Alembic.
+revision = '001'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        'user',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('email', sa.String(), nullable=False),
+        sa.Column('username', sa.String(), nullable=False),
+        sa.Column('hashed_password', sa.String(), nullable=False),
+        sa.Column('full_name', sa.String(), nullable=True),
+        sa.Column('is_active', sa.Boolean(), nullable=True, default=True),
+        sa.Column('is_superuser', sa.Boolean(), nullable=True, default=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=func.now(), nullable=True),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=func.now(), nullable=True),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_user_email'), 'user', ['email'], unique=True)
+    op.create_index(op.f('ix_user_id'), 'user', ['id'], unique=False)
+    op.create_index(op.f('ix_user_username'), 'user', ['username'], unique=True)
+
+
+def downgrade() -> None:
+    op.drop_index(op.f('ix_user_username'), table_name='user')
+    op.drop_index(op.f('ix_user_id'), table_name='user')
+    op.drop_index(op.f('ix_user_email'), table_name='user')
+    op.drop_table('user')
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..841d038
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,17 @@
+[tool.ruff]
+line-length = 100
+target-version = "py38"
+
+[tool.ruff.lint]
+select = [
+    "E",   # pycodestyle errors
+    "F",   # pyflakes
+    "I",   # isort
+    "W",   # pycodestyle warnings
+]
+ignore = [
+    "E501",  # line too long, handled by black
+]
+
+[tool.ruff.lint.isort]
+known-third-party = ["fastapi", "pydantic", "sqlalchemy", "jose", "passlib"]
\ No newline at end of file
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..27946db
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,11 @@
+fastapi>=0.104.0,<0.105.0
+uvicorn>=0.23.2,<0.24.0
+sqlalchemy>=2.0.23,<2.1.0
+alembic>=1.12.1,<1.13.0
+pydantic>=2.4.2,<2.5.0
+pydantic-settings>=2.0.3,<2.1.0
+python-jose[cryptography]>=3.3.0,<3.4.0
+passlib[bcrypt]>=1.7.4,<1.8.0
+python-multipart>=0.0.6,<0.1.0
+ruff>=0.1.5,<0.2.0
+pathlib>=1.0.1,<1.1.0
\ No newline at end of file