trio

A friendly Python library for async concurrency and I/O

trio Permissive license MIT OR Apache-2.0 Active ★ 7,305 v0.34.0 released 2026-08-11

Install

trio on PyPI

pip

pip install trio

uv

uv add trio

poetry

poetry add trio

Package facts

License	MIT OR Apache-2.0 (permissive)
Python support	supports the current Python release (>=3.10)
Install friction	low — pure-Python wheel
Runtime dependencies	7 — attrs, sortedcontainers, idna, outcome, sniffio, cffi, exceptiongroup
Maintenance	actively maintained — 2 days since the last release
Last repo commit	2026-08-11
First released	2017-01-14
Popularity	one of the top 1,000 most-downloaded packages on PyPI (30-day window, as of 2026-08-13)
Known vulnerabilities	none known (OSV.dev, checked 2026-08-13)

Evidence: trio-0.34.0-py3-none-any.whl

Keywords: async, io, networking, trio

Development Status :: 4 - BetaFramework :: TrioIntended Audience :: DevelopersOperating System :: MacOS :: MacOS XOperating System :: Microsoft :: WindowsOperating System :: POSIX :: BSDOperating System :: POSIX :: LinuxProgramming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: Implementation :: CPythonProgramming Language :: Python :: Implementation :: PyPyTopic :: System :: NetworkingTyping :: Typed

About trio

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Trio – a friendly Python library for async concurrency and I/O

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The Trio project aims to produce a production-quality, `permissively...

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AI interpretation — verify before relying

AI-generated interpretation of the package facts above; every digit, version, license, or vulnerability id it cites is grounded in the facts already shown on this page

Trio is a Python async I/O library built on structured concurrency principles, enabling you to write programs that handle multiple concurrent tasks and parallelized I/O operations with simpler, more readable code than traditional async frameworks.

Installation is straightforward with low friction: the package ships as a pure-Python wheel and all seven runtime dependencies (attrs, sortedcontainers, idna, outcome, sniffio, cffi, exceptiongroup) are either pure Python or have pre-built wheels. The project is actively maintained with a release just 2 days old, 7305 GitHub stars, and a solid track record since first release in 2017.

Trio is permissively licensed under MIT OR Apache-2.0, giving you the choice of either license. This dual licensing poses no legal friction for commercial or open-source use and aligns with the project's stated goal of being permissively licensed.

Usage

import trio

async def main():
    print("Hello from Trio")
    await trio.sleep(0)

trio.run(main)

Python 3.10 or later is required; the package supports CPython and PyPy3 on Linux, macOS, Windows, and FreeBSD.

Verdict: Trio is a mature, well-maintained async I/O library with zero known vulnerabilities, permissive licensing, and minimal install friction. Its focus on structured concurrency and usability makes it a solid choice for building concurrent applications, backed by active development and strong community engagement.

Needs verification

Whether the cffi dependency on Windows requires any special setup beyond wheel installation
Real-world performance characteristics compared to asyncio for specific workload patterns
Ecosystem maturity: availability and stability of third-party Trio-compatible libraries

async io library pythonstructured concurrency frameworkconcurrent networking pythonasyncio alternativeparallel io tasksasync await concurrencyevent loop python