# Flask Foundations

> Professional application architecture using the Factory Pattern and Blueprints in Flask.

- Skill: `jcorpac/flask-foundations` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add jcorpac/flask-foundations`
- Raw SKILL.md: https://api.skillmd.com/api/skills/jcorpac/flask-foundations/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: jcorpac (https://skillmd.com/u/jcorpac)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/jcorpac/flask-foundations

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# Flask Foundations

Flask is a micro-framework, but professional applications require structure to remain maintainable.

## Application Factory Pattern
Avoid global `app` objects. Instead, use a function to create the application instance.
- **Benefits**: Easier testing (multiple app instances), better configuration management, and avoidance of circular imports.
- **Pattern**: `def create_app(config_class=Config): ...`

## Blueprints
Organize your application into distinct components (e.g., `auth`, `api`, `main`).
- **Registration**: `app.register_blueprint(auth_bp, url_prefix='/auth')`
- **Utility**: Keeps codebases modular and allows for shared middleware/filters per component.

## Best Practices
- **Environment Config**: Use a `Config` class and `python-dotenv` for sensitive keys.
- **Lifecycle**: Understand `before_request`, `after_request`, and `teardown_appcontext`.