---
id: aiohttp-fast-zlib
version: "0.3.0"
license: Apache-2.0
license_treatment: permissive
maintenance: active
---

# aiohttp-fast-zlib — Use the fastest installed zlib compatible library with aiohttp

License: permissive · Maintenance: active · Downloads: 1.8M/mo

## What it is and what it does

aiohttp-fast-zlib is a thin wrapper that swaps aiohttp's compression layer to use faster zlib-compatible libraries. Compression is a known bottleneck in aiohttp, especially for WebSocket connections that compress frequently; this package patches aiohttp to use isal or zlib-ng instead of the standard library's zlib, both of which are drop-in replacements with better performance. You call a single enable() function at startup, and all subsequent aiohttp compression operations use the faster library.

The package is in Pre-Alpha development, meaning the API and behavior may change. It has a single runtime dependency on aiohttp and requires Python 3.9 or later. Installation is straightforward, but you must also install one of the optional compression libraries (isal or zlib-ng) to see any benefit.

Use it for:

- Speed up WebSocket communication in aiohttp applications by reducing compression CPU overhead.
- Improve throughput for HTTP APIs that heavily compress responses (JSON, HTML, etc.).
- Reduce latency in real-time aiohttp services where zlib compression is a measurable bottleneck.
- Optimize resource usage on servers handling many concurrent aiohttp connections.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Replaces aiohttp's default zlib compression with faster alternatives (isal or zlib-ng) to reduce compression bottlenecks in HTTP and WebSocket connections.

Yes, if you use aiohttp and compression is a known bottleneck in your workload. The package is low-friction to install and maintain, has no known vulnerabilities, and offers a straightforward performance win. Pre-Alpha status means you should test it in a non-critical environment first and monitor for API changes in future releases.

## Install

pip install aiohttp-fast-zlib
uv add aiohttp-fast-zlib
poetry add aiohttp-fast-zlib

## Installing aiohttp-fast-zlib

Before you install: Low friction: pure Python wheel with a single runtime dependency (aiohttp). Actively maintained with recent commits. Pre-Alpha status signals the package is still stabilizing, so expect potential API changes.

License in practice: Apache-2.0 permissive license allows commercial and private use with minimal restrictions; you must retain license notices in distributions.

Quickstart:

pip install aiohttp-fast-zlib[isal]

import aiohttp_fast_zlib
aiohttp_fast_zlib.enable()

Requires either isal or zlib-ng to be installed as an optional extra; without one, the package will not provide a performance benefit.

Verify before relying:

- Whether isal or zlib-ng must be pre-installed or are automatically pulled in by the extras.
- Specific performance gains (percentage improvement) over standard aiohttp compression.
- Compatibility with all aiohttp versions or specific version constraints.

## Package facts

- License: Apache-2.0 (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 1.8M/month (top 5,000 on PyPI)
- Known vulnerabilities: none known

## Tags

aiohttp compression performance, zlib optimization aiohttp, fast compression websockets, isal zlib-ng wrapper, http compression speedup, aiohttp deflate faster, compression-optimization, websocket-performance

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