7 Useful Middlewares for FastAPI That You Should Know About 🚀

FastAPI is fast — but with the right middleware, it becomes unstoppable.

7 Useful Middlewares for FastAPI That You Should Know About 🚀

FastAPI has rapidly become one of the most popular web frameworks in the Python ecosystem — and for good reason. It’s fast, intuitive, and perfectly tailored for modern web APIs. But if you’re not using middleware effectively, you’re missing out on a powerful tool to supercharge your app’s performance, security, and maintainability.

In this article, we’ll explore 7 super handy FastAPI middlewares that can help you build cleaner, more secure, and more efficient APIs.

How to Structure Your FastAPI Projects (The Right Way)

Master the art of structuring FastAPI apps like a pro — whether you’re building APIs solo or scaling with a team.

But First, What’s Middleware?

In FastAPI (and Starlette, the ASGI toolkit underneath), middleware is a function or class that runs before and/or after each request. You can use it to log data, handle errors, enforce security, and more — without cluttering your route logic.

Now let’s dive into some powerful middleware you should consider using in your next project.

1. CORS Middleware

Problem it solves: Prevents browser-related security errors when making requests from another domain.

from fastapi import FastAPI 
from fastapi.middleware.cors import CORSMiddleware 
 
app = FastAPI() 
 
app.add_middleware( 
    CORSMiddleware, 
    allow_origins=["*"],  # or specify trusted domains 
    allow_credentials=True, 
    allow_methods=["*"], 
    allow_headers=["*"], 
)

Why you need it: If you’re building a frontend in React, Vue, or any JS framework that talks to your FastAPI backend, CORS middleware is a must.

2. GZip Middleware

Problem it solves: Reduces response size and speeds up response time.

from fastapi.middleware.gzip import GZipMiddleware 
 
app.add_middleware(GZipMiddleware, minimum_size=1000)

Why you need it: GZip compresses large responses, saving bandwidth and improving load time, especially for clients on slower networks.

3. Request Logging Middleware

Problem it solves: Helps you track incoming requests, useful for debugging and analytics.

from starlette.middleware.base import BaseHTTPMiddleware 
import time 
 
class LoggingMiddleware(BaseHTTPMiddleware): 
    async def dispatch(self, request, call_next): 
        start_time = time.time() 
        response = await call_next(request) 
        duration = round(time.time() - start_time, 4) 
        print(f"{request.method} {request.url.path} - {duration}s") 
        return response 
 
app.add_middleware(LoggingMiddleware)

Why you need it: This middleware gives visibility into what’s hitting your API — great for monitoring and debugging in development or production.

4. Trusted Host Middleware

Problem it solves: Prevents HTTP Host header attacks.

from fastapi.middleware.trustedhost import TrustedHostMiddleware 
 
app.add_middleware( 
    TrustedHostMiddleware, allowed_hosts=["example.com", "*.example.com"] 
)

Why you need it: It’s a simple yet powerful security measure to reject requests with unexpected Host headers — protecting you from DNS rebinding attacks.

5. HTTPS Redirect Middleware

Problem it solves: Ensures users are always using HTTPS.

from starlette.middleware.httpsredirect import HTTPSRedirectMiddleware 
 
app.add_middleware(HTTPSRedirectMiddleware)

Why you need it: Automatically redirects all HTTP requests to HTTPS — an essential step if you’re serving your app over the web and want to enforce encryption.

6. Custom Exception Handling Middleware

Problem it solves: Centralizes error handling logic.

from starlette.middleware.base import BaseHTTPMiddleware 
from starlette.responses import JSONResponse 
 
class ExceptionMiddleware(BaseHTTPMiddleware): 
    async def dispatch(self, request, call_next): 
        try: 
            return await call_next(request) 
        except Exception as e: 
            return JSONResponse({"error": str(e)}, status_code=500) 
 
app.add_middleware(ExceptionMiddleware)

Why you need it: Instead of handling errors route-by-route, you can catch and format them consistently across your app with one simple middleware.

7. Rate Limiting Middleware (Using Third-Party Library)

Problem it solves: Protects your API from abuse by limiting how many requests a user can make.

Install slowapi:

pip install slowapi

Then set it up:

from fastapi import FastAPI, Request 
from slowapi import Limiter, _rate_limit_exceeded_handler 
from slowapi.util import get_remote_address 
from slowapi.errors import RateLimitExceeded 
 
limiter = Limiter(key_func=get_remote_address) 
app = FastAPI() 
 
app.state.limiter = limiter 
app.add_exception_handler(RateLimitExceeded, _rate_limit_exceeded_handler) 
 
@app.get("/limited") 
@limiter.limit("5/minute") 
async def limited_endpoint(request: Request): 
    return {"message": "This endpoint is rate-limited"}

Why you need it: It’s an essential protection against DDoS attacks, bot abuse, or poorly written clients hammering your endpoints.

Bonus Tip: Middleware Order Matters!

Middlewares are applied in the order they are added. So, if you’re seeing odd behavior, double-check the sequence — especially when combining security and performance-related middlewares.

Wrapping Up

Middlewares are like power-ups for your FastAPI app. From logging and security to compression and throttling, they help you write cleaner code while taking care of essential backend concerns.

Next time you spin up a FastAPI project, reach into this toolbox and plug in the ones that fit your use case.

Got a favorite middleware that we missed? Drop it in the comments or let’s connect — I’d love to hear how you’re using FastAPI in your projects!

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