fastapi

Structure FastAPI applications with routers, dependency injection, and JWT authentication.

186|15|Updated Apr 2, 2026

Search Tags:#testing #authentication #pydantic #fastapi #python #web api #dependency-injection

Ready to run

npx skills add https://github.com/kid-sid/claude-spellbook --skill fastapi-kid-sid

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: fastapi
Source: https://github.com/kid-sid/claude-spellbook/tree/main/skills/fastapi
Command: npx skills add https://github.com/kid-sid/claude-spellbook --skill fastapi-kid-sid

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Establishes scalable, maintainable FastAPI projects by documenting best practices for app structure, dependency injection, schemas, authentication, and testing.

Core Features & Use Cases

App factory with lifespan management to initialize singletons and close resources
Modular routing and layered architecture with routers and dependencies
Pydantic v2 schemas and type-safe models across API boundaries
JWT/OAuth2 authentication, error handling, and middleware patterns
Testing scaffolds for route tests and CI-friendly workflows
WebSocket, background tasks, and API design best practices

Quick Start

Scaffold a FastAPI project using this guide to implement routers, dependency injection, and authentication.

Frequently Asked Questions about fastapi

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I structure a FastAPI application with modular routers and dependency injection?▼

To structure a FastAPI application, use an app factory pattern with lifespan management to initialize singletons, then organize endpoints into modular routers with layered dependencies for maintainable separation of concerns.

How does dependency injection work in FastAPI for managing database connections?▼

FastAPI dependency injection uses callable functions or classes that provide resources like database sessions, allowing routers to declare dependencies explicitly and automatically closing resources via lifespan management.

What is the best way to implement JWT authentication in a FastAPI project?▼

The best way to implement JWT authentication in FastAPI involves using OAuth2 password flow with Pydantic v2 schemas to validate tokens, applying middleware to protect routes and handle authentication errors consistently.

Can I use Pydantic v2 models for request and response schemas in FastAPI?▼

Yes, you can use Pydantic v2 models to define type-safe request and response schemas across API boundaries, ensuring automatic validation and serialization for incoming and outgoing data payloads.

How do I set up testing scaffolds for FastAPI routes?▼

Set up FastAPI testing scaffolds by creating route tests that use the dependency injection system to override real database connections, enabling CI-friendly workflows that validate endpoints in isolation.

Does FastAPI support WebSockets and background tasks within a modular app structure?▼

FastAPI supports WebSockets and background tasks within a modular app structure by organizing them into dedicated routers and dependencies, ensuring asynchronous operations remain maintainable across multiple modules.