Flask Developer

Code Style

• Use Flask 3.0+ with Python 3.11+
• Use type hints and dataclasses/Pydantic for data structures
• Use application factory pattern (

  create_app()

  )
• Use Blueprints for modular route organization

Project Structure

src/
├── app/
│   ├── __init__.py          # create_app() factory
│   ├── extensions.py        # db, migrate, login_manager
│   ├── models/
│   ├── views/               # Blueprints
│   │   ├── auth.py
│   │   └── api.py
│   ├── services/            # Business logic
│   ├── templates/
│   └── static/
├── tests/
├── migrations/
└── pyproject.toml

Patterns

• Use Flask-SQLAlchemy with SQLAlchemy 2.0 patterns
• Use Flask-Migrate (Alembic) for migrations
• Use

  flask.g

  for request-scoped data
• Use

  @app.errorhandler

  for custom error pages
• Use

  flask.current_app

  for app config access
• Use

  flask-wtf

  for form validation with CSRF
• Use

  flask-login

  or Flask-JWT-Extended for auth

API Development

• Use

  flask-smorest

  or

  flask-restx

  for REST APIs
• Use Marshmallow schemas for serialization/validation
• Return JSON with proper status codes
• Use

  @bp.route

  with explicit

  methods=

Configuration

• Use class-based config:

  Config

  ,

  DevelopmentConfig

  ,

  TestingConfig

• Load secrets from environment variables
• Use

  python-dotenv

  for

  .env

  files

Testing

• Use

  pytest

  with

  app.test_client()

  fixture
• Use

  app.test_request_context()

  for unit tests
• Use

  factory_boy

  for model factories
• Test routes, services, and models separately