1---
2name: fastapi-templates
3description: Create production-ready FastAPI projects with async patterns, dependency injection, and comprehensive error handling. Use when building new FastAPI applications or setting up backend API projects.
4---
5 
6# FastAPI Project Templates
7 
8Production-ready FastAPI project structures with async patterns, dependency injection, middleware, and best practices for building high-performance APIs.
9 
10## When to Use This Skill
11 
12- Starting new FastAPI projects from scratch
13- Implementing async REST APIs with Python
14- Building high-performance web services and microservices
15- Creating async applications with PostgreSQL, MongoDB
16- Setting up API projects with proper structure and testing
17 
18## Core Concepts
19 
20### 1. Project Structure
21 
22**Recommended Layout:**
23 
24```
25app/
26├── api/                    # API routes
27│   ├── v1/
28│   │   ├── endpoints/
29│   │   │   ├── users.py
30│   │   │   ├── auth.py
31│   │   │   └── items.py
32│   │   └── router.py
33│   └── dependencies.py     # Shared dependencies
34├── core/                   # Core configuration
35│   ├── config.py
36│   ├── security.py
37│   └── database.py
38├── models/                 # Database models
39│   ├── user.py
40│   └── item.py
41├── schemas/                # Pydantic schemas
42│   ├── user.py
43│   └── item.py
44├── services/               # Business logic
45│   ├── user_service.py
46│   └── auth_service.py
47├── repositories/           # Data access
48│   ├── user_repository.py
49│   └── item_repository.py
50└── main.py                 # Application entry
51```
52 
53### 2. Dependency Injection
54 
55FastAPI's built-in DI system using `Depends`:
56 
57- Database session management
58- Authentication/authorization
59- Shared business logic
60- Configuration injection
61 
62### 3. Async Patterns
63 
64Proper async/await usage:
65 
66- Async route handlers
67- Async database operations
68- Async background tasks
69- Async middleware
70 
71## Detailed worked examples and patterns
72 
73Detailed sections (starting with `## Implementation Patterns`) live in `references/details.md`. Read that file when the navigation summary above is insufficient.
74 
75## Testing
76 
77```python
78# tests/conftest.py
79import pytest
80import asyncio
81from httpx import AsyncClient
82from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession
83from sqlalchemy.orm import sessionmaker
84 
85from app.main import app
86from app.core.database import get_db, Base
87 
88TEST_DATABASE_URL = "sqlite+aiosqlite:///:memory:"
89 
90@pytest.fixture(scope="session")
91def event_loop():
92    loop = asyncio.get_event_loop_policy().new_event_loop()
93    yield loop
94    loop.close()
95 
96@pytest.fixture
97async def db_session():
98    engine = create_async_engine(TEST_DATABASE_URL, echo=True)
99    async with engine.begin() as conn:
100        await conn.run_sync(Base.metadata.create_all)
101 
102    AsyncSessionLocal = sessionmaker(
103        engine, class_=AsyncSession, expire_on_commit=False
104    )
105 
106    async with AsyncSessionLocal() as session:
107        yield session
108 
109@pytest.fixture
110async def client(db_session):
111    async def override_get_db():
112        yield db_session
113 
114    app.dependency_overrides[get_db] = override_get_db
115 
116    async with AsyncClient(app=app, base_url="http://test") as client:
117        yield client
118 
119# tests/test_users.py
120import pytest
121 
122@pytest.mark.asyncio
123async def test_create_user(client):
124    response = await client.post(
125        "/api/v1/users/",
126        json={
127            "email": "[email protected]",
128            "password": "testpass123",
129            "name": "Test User"
130        }
131    )
132    assert response.status_code == 201
133    data = response.json()
134    assert data["email"] == "[email protected]"
135    assert "id" in data
136```
137