aiohttp vs httpx vs requests

Choosing an HTTP client in Python can feel confusing. Three libraries dominate the space: requests, aiohttp, and httpx.

Each one solves a different problem. Picking the wrong one can slow your app or force a rewrite later.

This guide breaks down all three. You will see real code, output, and clear advice on when to use each one.

Quick Overview

requests is the classic, simple, synchronous library. It is the most popular HTTP client in Python history.

aiohttp is built for asyncio. It handles thousands of concurrent requests with one thread.

httpx is the modern hybrid. It supports both sync and async code with one clean API.

Let's look at each library in detail.

requests: The Familiar Standard

The requests library has been the go-to choice since 2011. Its API is friendly and readable.

Here is a basic GET request:

import requests

# Send a simple GET request
response = requests.get("https://httpbin.org/get")

# Check the status code
print(response.status_code)

# Print the JSON body
print(response.json()["url"])

200
https://httpbin.org/get

It is clean and easy to read. Beginners love it for a reason.

But requests is synchronous. Each call blocks until the server responds.

If you need 1,000 requests, you wait for 1,000 round trips. That is slow.

You can use threads to work around this. But threads add complexity and overhead.

When to Use requests

Use requests for scripts, small tools, and simple automation.

It is also great when your app is already synchronous. There is no need to add async complexity.

The library is stable, well-documented, and battle-tested. It rarely surprises you.

aiohttp: Built for Async Speed

aiohttp is an asynchronous HTTP client and server framework. It runs on top of asyncio.

It shines when you need many concurrent requests. Think web scrapers, API aggregators, or real-time apps.

Here is an async GET request:

import aiohttp
import asyncio

async def main():
    # Open an async session
    async with aiohttp.ClientSession() as session:
        # Send a GET request
        async with session.get("https://httpbin.org/get") as response:
            # Read the JSON body
            data = await response.json()
            print(response.status)
            print(data["url"])

# Run the async function
asyncio.run(main())

200
https://httpbin.org/get

Notice the async with and await keywords. Everything is non-blocking.

You can fire hundreds of requests at once. The event loop handles them efficiently.

This makes aiohttp extremely fast for I/O-heavy tasks.

Downsides of aiohttp

The async syntax has a learning curve. Beginners often struggle with event loops.

You cannot use aiohttp in normal synchronous code. It requires an async context.

It also has a more complex API than requests. Sessions, connectors, and timeouts need care.

When to Use aiohttp

Use aiohttp when you need high concurrency and your app is already async.

It is a strong choice for web scrapers and microservices that handle many connections.

httpx: The Modern All-Rounder

httpx is the newest of the three. It aims to combine the best of both worlds.

It offers a requests-like API with full async support. You can write sync or async code with the same library.

Here is a synchronous example:

import httpx

# Sync request, similar to requests
response = httpx.get("https://httpbin.org/get")

print(response.status_code)
print(response.json()["url"])

200
https://httpbin.org/get

Now the async version:

import httpx
import asyncio

async def main():
    # Async client with connection pooling
    async with httpx.AsyncClient() as client:
        response = await client.get("https://httpbin.org/get")
        print(response.status_code)
        print(response.json()["url"])

asyncio.run(main())

200
https://httpbin.org/get

Same library, two styles. That flexibility is powerful.

httpx also supports HTTP/2, which requests does not. This can improve performance on modern servers.

It has built-in timeout handling, retries, and a clean client interface.

When to Use httpx

Use httpx when you want modern features and flexibility. It is ideal for new projects.

It is also the best choice if you may switch between sync and async later.

Performance Comparison

For a single request, all three are similar. The difference appears at scale.

requests blocks on each call. With 100 requests, you wait for all 100.

aiohttp and httpx run concurrently. They can finish 100 requests in the time of the slowest one.

In benchmarks, async clients often handle 10x to 50x more requests per second.

But async is not always faster. For a few requests, the overhead of an event loop can slow you down.

Match the tool to the workload. Do not use async for three requests.

Feature Comparison Table

Here is a quick side-by-side look:

requests: sync only, HTTP/1.1, simple API, huge ecosystem.

aiohttp: async only, HTTP/1.1, fast concurrency, server support.

httpx: sync and async, HTTP/2, modern API, great typing.

Each has strengths. None is universally best.

Common Mistakes to Avoid

Do not mix blocking code inside async functions. It freezes the event loop.

Always close sessions and clients. Leaked connections cause errors and slowdowns.

Set timeouts. Without them, a slow server can hang your app forever.

Reuse clients across requests. Creating a new one each time is wasteful.

Which Should You Choose?

Pick requests for simple, synchronous tasks. It is reliable and easy.

Pick aiohttp for high-concurrency async apps that need raw speed.

Pick httpx for modern projects that want flexibility and HTTP/2.

If you are unsure, start with httpx. It covers almost every use case.

Conclusion

requests, aiohttp, and httpx are all excellent libraries. Each fits a specific need.

Use requests for simplicity. Use aiohttp for async performance. Use httpx for modern, flexible development.

Think about your concurrency needs and your team's comfort with async. Then choose with confidence.