uvloop
Fast implementation of asyncio event loop on top of libuv
Decision gist · record as of 2026-08-14
Yes, if you use asyncio and need better performance. uvloop is production-stable, actively maintained, has no external dependencies, and offers a straightforward integration path. The main consideration is install friction on systems without prebuilt wheels; otherwise, it is a low-risk, high-reward upgrade for async workloads.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.8.1 or later.
- On systems without prebuilt wheels, a C compiler is needed to build from source.
- Medium install friction due to compiled wheels; prebuilt binaries are available for Python 3.8–3.13 on macOS, Linux, and musl systems, but source builds require a C compiler.
License · maintenance · safety
MIT License (permissive) — Dual-licensed under MIT and Apache 2.0, both permissive licenses. You may use, modify, and distribute uvloop freely under either license with minimal restrictions.
last release 2025-10-16 (302 days) · last repo commit 2026-07-14 · 11,884 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 257,903,364 downloads/mo, #155 on PyPI
Alternatives
Verify before relying
import uvloop
async def main():
# Your async code here
pass
uvloop.run(main())- Whether the 2-4x performance claim applies to your specific workload and message sizes.
- Whether libuv's platform-specific behavior (e.g., on Windows) affects your use case, as prebuilt wheels are limited to Unix-like systems.
What it is and what it does
uvloop is a high-performance event loop for Python's asyncio framework that replaces the default implementation with a faster one built on libuv, a mature C library used by Node.js. It is designed as a drop-in replacement: you can swap it in with minimal code changes and immediately benefit from lower latency and higher throughput in async I/O operations.
The package is implemented in Cython and compiles to native code, so it requires either prebuilt wheels for your platform or a C compiler to build from source. It supports Python 3.8 through 3.13 and is actively maintained. Because it is a core runtime component, it has no external Python dependencies, making it lightweight to integrate into existing async applications.
Use it for
- Accelerate web servers and APIs built with asyncio, aiohttp, or FastAPI without changing application code.
- Improve throughput in high-concurrency network services that handle many simultaneous connections.
- Speed up async database drivers and I/O-bound applications that rely on asyncio.
- Optimize real-time applications like chat servers or streaming services that depend on event loop performance.
- Replace the default event loop in production deployments where asyncio latency is a bottleneck.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you use asyncio and need better performance.
uvloop is production-stable, actively maintained, has no external dependencies, and offers a straightforward integration path. The main consideration is install friction on systems without prebuilt wheels; otherwise, it is a low-risk, high-reward upgrade for async workloads.
Install
uvloop on PyPI
Before you install
Medium install friction due to compiled wheels; prebuilt binaries are available for Python 3.8–3.13 on macOS, Linux, and musl systems, but source builds require a C compiler. The project is actively maintained with recent commits and is production-stable.
Requires Python 3.8.1 or later. On systems without prebuilt wheels, a C compiler is needed to build from source.
License in practice
Dual-licensed under MIT and Apache 2.0, both permissive licenses. You may use, modify, and distribute uvloop freely under either license with minimal restrictions.
Quickstart
import uvloop
async def main():
# Your async code here
pass
uvloop.run(main())Verify before relying
- Whether the 2-4x performance claim applies to your specific workload and message sizes.
- Whether libuv's platform-specific behavior (e.g., on Windows) affects your use case, as prebuilt wheels are limited to Unix-like systems.
Package facts
| License | MIT License permissive |
| Python support | Supports the current Python release >=3.8.1 |
| Install friction | Medium. Platform-specific wheel |
| Runtime dependencies | None |
| Maintenance | Actively maintained 302 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 257,903,364 / month, #155 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableFramework :: AsyncIOIntended Audience :: DevelopersLicense :: OSI Approved :: Apache Software LicenseLicense :: OSI Approved :: MIT LicenseOperating System :: MacOS :: MacOS XOperating System :: POSIXProgramming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Programming Language :: Python :: Implementation :: CPythonTopic :: System :: Networking |
Evidence: uvloop-0.22.1-cp310-cp310-macosx_10_9_universal2.whl; uvloop-0.22.1-cp310-cp310-macosx_10_9_x86_64.whl; uvloop-0.22.1-cp310-cp310-manylinux2014_aarch64.manylinux_2_17_aarch64.manylinux_2_28_aarch64.whl; uvloop-0.22.1-cp310-cp310-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl; uvloop-0.22.1-cp310-cp310-musllinux_1_2_aarch64.whl; uvloop-0.22.1-cp310-cp310-musllinux_1_2_x86_64.whl; uvloop-0.22.1-cp311-cp311-macosx_10_9_universal2.whl; uvloop-0.22.1-cp311-cp311-macosx_10_9_x86_64.whl; uvloop-0.22.1-cp311-cp311-manylinux2014_aarch64.manylinux_2_17_aarch64.manylinux_2_28_aarch64.whl; uvloop-0.22.1-cp311-cp311-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl; uvloop-0.22.1-cp311-cp311-musllinux_1_2_aarch64.whl; uvloop-0.22.1-cp311-cp311-musllinux_1_2_x86_64.whl; uvloop-0.22.1-cp312-cp312-macosx_10_13_universal2.whl; uvloop-0.22.1-cp312-cp312-macosx_10_13_x86_64.whl; uvloop-0.22.1-cp312-cp312-manylinux2014_aarch64.manylinux_2_17_aarch64.manylinux_2_28_aarch64.whl; uvloop-0.22.1-cp312-cp312-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl; uvloop-0.22.1-cp312-cp312-musllinux_1_2_aarch64.whl; uvloop-0.22.1-cp312-cp312-musllinux_1_2_x86_64.whl; uvloop-0.22.1-cp313-cp313-macosx_10_13_universal2.whl; uvloop-0.22.1-cp313-cp313-macosx_10_13_x86_64.whl
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