Skill: Flask

Best practices for Flask web development including routing, blueprints, and testing.

When to Use

Apply this skill when building Flask web applications or APIs — routing, blueprints, extensions, and testing.

Project Structure

• Use the application factory pattern (create_app()) to avoid global state and enable testing.
• Organize features into Blueprints; register them in the factory.
• Keep configuration in a config.py with classes like DevelopmentConfig, ProductionConfig.

Routing and Views

• Prefer explicit HTTP method decorators (@app.get, @app.post) over generic @app.route with methods=[...].
• Validate request data early; return 400 errors for malformed input before processing.
• Use flask.abort() with appropriate HTTP codes rather than returning error responses manually.