fastapi-development

SKILL.md

FastAPI Development

Table of Contents

Overview

When to Use

Quick Start

Reference Guides

Best Practices

Overview

Create fast, modern Python APIs using FastAPI with async/await support, automatic API documentation, type validation using Pydantic, dependency injection, JWT authentication, and SQLAlchemy ORM integration.

When to Use

Building high-performance Python REST APIs

Creating async API endpoints

Implementing automatic OpenAPI/Swagger documentation

Leveraging Python type hints for validation

Building microservices with async support

Integrating Pydantic for data validation

Quick Start

Minimal working example:

# main.py
from fastapi import FastAPI, HTTPException, status
from fastapi.middleware.cors import CORSMiddleware
from contextlib import asynccontextmanager
import logging

# Setup logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# Create FastAPI instance
app = FastAPI(
    title="API Service",
    description="A modern FastAPI application",
    version="1.0.0",
    docs_url="/api/docs",
    openapi_url="/api/openapi.json"
)

# Add CORS middleware
app.add_middleware(
    CORSMiddleware,
    allow_origins=["http://localhost:3000"],
    allow_credentials=True,
    allow_methods=["*"],
// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the references/ directory:

Guide
Contents

FastAPI Application Setup
FastAPI Application Setup

Pydantic Models for Validation
Pydantic Models for Validation

Async Database Models and Queries
Async Database Models and Queries

Security and JWT Authentication
Security and JWT Authentication

Service Layer for Business Logic
Service Layer for Business Logic

API Routes with Async Endpoints
API Routes with Async Endpoints

Best Practices

✅ DO

Use async/await for I/O operations

Leverage Pydantic for validation

Use dependency injection for services

Implement proper error handling with HTTPException

Use type hints for automatic OpenAPI documentation

Create service layers for business logic

Implement authentication on protected routes

Use environment variables for configuration

Return appropriate HTTP status codes

Document endpoints with docstrings and tags

❌ DON'T

Use synchronous database operations

Trust user input without validation

Store secrets in code

Ignore type hints

Return database models in responses

Implement authentication in route handlers

Use mutable default arguments

Forget to validate query parameters

Expose stack traces in production

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