Custom Status Codes 🎨

While HTTP defines standard status codes, you can use custom codes for specific scenarios.

Common Custom Scenarios

from fastapi import status

# 202 Accepted - Async processing
@app.post("/process", status_code=status.HTTP_202_ACCEPTED)
async def process_async(data: dict):
    queue.enqueue(process_task, data)
    return {"status": "processing"}

# 206 Partial Content - Partial response
@app.get("/items", status_code=status.HTTP_206_PARTIAL_CONTENT)
async def list_items_partial(limit: int = 10):
    return {"items": db.list_items(limit)}

# 429 Too Many Requests - Rate limiting
@app.get("/api/data")
async def get_data():
    if rate_limited():
        raise HTTPException(
            status_code=status.HTTP_429_TOO_MANY_REQUESTS,
            detail="Rate limit exceeded"
        )
    return {"data": []}

Status Code Constants

from fastapi import status

# Use constants instead of magic numbers
@app.post("/items", status_code=status.HTTP_201_CREATED)
async def create_item(item: Item):
    return item

# Available constants:
# - HTTP_200_OK
# - HTTP_201_CREATED
# - HTTP_204_NO_CONTENT
# - HTTP_400_BAD_REQUEST
# - HTTP_404_NOT_FOUND
# - HTTP_500_INTERNAL_SERVER_ERROR
# ... and many more

🔑 Key Takeaways

• ✅ Use status constants for clarity

• ✅ 202 for async processing

• ✅ 206 for partial responses

• ✅ 429 for rate limiting