flake8-async
A highly opinionated flake8 plugin for Trio-related problems.
Decision gist · record as of 2026-08-14
Yes, if you write async code with Trio, AnyIO, or asyncio and want linting coverage beyond general flake8 checks. The low install friction, active maintenance, MIT license, and zero known vulnerabilities make it a safe addition. Be aware it is opinionated and may flag code you consider acceptable; review its rule documentation to decide if its strictness matches your team's standards.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.9 or later and an existing flake8 installation.
- Low friction installation with a single runtime dependency (libcst).
- The project is actively maintained with a recent release and no known vulnerabilities.
License · maintenance · safety
MIT (permissive) — MIT license is permissive; you can use this plugin freely in commercial and private projects with minimal restrictions.
last release 2026-07-28 (17 days) · last repo commit 2026-08-10 · 27 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 351,920 downloads/mo, #7,317 on PyPI
Alternatives
Verify before relying
pip install flake8-async
# Then run flake8 on your async code:
flake8 your_async_file.py
# The plugin integrates automatically with flake8 and reports ASYNC-prefixed errors.- Whether the plugin's checks overlap significantly with ruff's async checks or if they complement each other.
- How noisy the checks are in typical async codebases and whether filtering is commonly needed.
What it is and what it does
flake8-async is a flake8 plugin that integrates async-specific linting rules for Trio, AnyIO, and asyncio code. It detects a range of issues from outright bugs to idiom violations that may signal misunderstandings of async patterns. The plugin reports problems using ASYNC-prefixed error codes and is designed to catch issues that general linters might miss in async contexts.
The plugin depends on libcst for code parsing and integrates directly into flake8's workflow. It is actively maintained and supports Python 3.9 through 3.13. The description notes it can be opinionated and potentially noisy depending on your coding style, and suggests pairing it with flake8-bugbear for broader coverage.
Use it for
- Catch common async bugs and antipatterns in Trio-based applications before they reach production.
- Enforce consistent async idioms across a team's asyncio or AnyIO codebases during code review.
- Identify dead or pointless async code that may indicate misunderstanding of concurrency patterns.
- Detect likely performance issues in async functions that could cause bottlenecks or blocking.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you write async code with Trio, AnyIO, or asyncio and want linting coverage beyond general flake8 checks.
The low install friction, active maintenance, MIT license, and zero known vulnerabilities make it a safe addition. Be aware it is opinionated and may flag code you consider acceptable; review its rule documentation to decide if its strictness matches your team's standards.
Install
flake8-async on PyPI
Before you install
Low friction installation with a single runtime dependency (libcst). The project is actively maintained with a recent release and no known vulnerabilities.
Requires Python 3.9 or later and an existing flake8 installation.
License in practice
MIT license is permissive; you can use this plugin freely in commercial and private projects with minimal restrictions.
Quickstart
pip install flake8-async
# Then run flake8 on your async code:
flake8 your_async_file.py
# The plugin integrates automatically with flake8 and reports ASYNC-prefixed errors.Verify before relying
- Whether the plugin's checks overlap significantly with ruff's async checks or if they complement each other.
- How noisy the checks are in typical async codebases and whether filtering is commonly needed.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release >=3.9 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 1 packagelibcst |
| Maintenance | Actively maintained 17 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 351,920 / month, #7,317 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 3 - AlphaFramework :: Flake8Intended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.9 |
Evidence: flake8_async-26.7.1-py3-none-any.whl
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