fastapi

name	fastapi
description	FastAPI — modern async Python web framework on Starlette + Pydantic v2 with auto-generated OpenAPI 3.1. Use when: fastapi, fast api, FastAPI, async python api, python rest api, pydantic-backed api, async/await python web, path operation, APIRouter, include_router, Depends, sub-dependencies, dependencies with yield, BaseModel response, response_model, OAuth2PasswordBearer, OAuth2PasswordRequestForm, SecurityScopes, JWT python-jose PyJWT, passlib bcrypt argon2, CORSMiddleware, TrustedHostMiddleware, GZipMiddleware, lifespan asynccontextmanager, BackgroundTasks, StreamingResponse, EventSourceResponse, WebSocket, TestClient, AsyncClient httpx, dependency_overrides, uvicorn, gunicorn UvicornWorker, openapi auto-doc, Swagger UI, ReDoc. SKIP: Django (→django cascade), Flask (→flask cascade), Node frameworks (→fastify/hono), pure Pydantic schemas (→pydantic), SQLAlchemy ORM specifics (→sqlalchemy cascade).
stacks	["fastapi","python","backend"]
tags	["fastapi","python","api","async","rest","pydantic","openapi"]
packages	["fastapi","uvicorn","gunicorn","python-multipart","python-jose","passlib","httpx","pydantic"]
manifests	["pyproject.toml","requirements.txt"]
source	vechkasov-global-skills
risk	high-stakes

🎯 Version Requirements (May 2026)

Primary pins:

• FastAPI: 0.136.x
• Pydantic: 2.13.x
• Python: 3.14.x

Source of truth: STACK_VERSIONS.md — verified 2026-05-16

Usage

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Use this skill when

• Building or migrating a production HTTP API in Python with FastAPI (async-first, Pydantic v2)
• Designing path operations with typed Annotated[T, Depends(...)], Path, Query, Body, Form, File, Header, Cookie
• Declaring request/response shapes with Pydantic BaseModel + response_model, status codes, multiple response types
• Composing modules via APIRouter, include_router(..., prefix=, tags=, dependencies=)
• Building dependency graphs — Depends, sub-dependencies, classes as dependencies, yield cleanup, global dependencies, dependency_overrides for tests
• Wiring security: OAuth2PasswordBearer, OAuth2PasswordRequestForm, SecurityScopes, JWT issuance/validation, password hashing
• Configuring middleware: CORSMiddleware, TrustedHostMiddleware, GZipMiddleware, HTTPSRedirectMiddleware, custom @app.middleware("http"), exception_handler
• Replacing legacy @app.on_event("startup"/"shutdown") with the lifespan async context manager
• Returning streamed data — StreamingResponse, SSE via EventSourceResponse, FileResponse, WebSockets
• Wiring async SQLAlchemy 2.0 + Alembic with a per-request AsyncSession dependency
• Generating OpenAPI 3.1 docs, customizing /docs (Swagger UI) and /redoc, generating typed clients