syncer
Async to sync converter
What it is and what it does
Syncer is a lightweight utility that wraps async functions and coroutines to run them synchronously, eliminating the need to call asyncio.get_event_loop().run_until_complete() directly. It has no runtime dependencies and works by managing the event loop internally.
The package is most useful in testing scenarios where you need to call async code from synchronous test functions or decorators, or when you have a synchronous codebase that needs to consume async libraries. It can be used as a decorator or called directly on a coroutine to get its result synchronously.
Use it for:
- Run async test functions synchronously in unittest or pytest without rewriting test infrastructure.
- Call async library functions from synchronous code without manually managing event loops.
- Decorate async test methods to make them compatible with synchronous test runners.
- Evaluate coroutines in a REPL or script without boilerplate event loop setup.
- Integrate async code into legacy synchronous applications during migration.
Worth the install?
AI-flagged interpretation of the facts on this page — verify before relying
Syncer converts async functions to synchronous callables, allowing you to run coroutines synchronously without manually managing event loops.
Yes, if you need to run async code synchronously in tests or legacy code. The package is simple, has no dependencies, and carries no security vulnerabilities. However, the dormant maintenance status (last release over a year ago) means you should verify it works with your Python version and be prepared to fork or find alternatives if asyncio internals change significantly in future Python releases.
Install
syncer on PyPI
pip
pip install synceruv
uv add syncerpoetry
poetry add syncerInstalling syncer
Before you install
High install friction with no runtime dependencies. The package is dormant—last release was 2023-05-08, over a year ago, with no commits since 2023-11-08. It remains marked Production/Stable and supports Python 3.8–3.11, but the long inactivity means maintenance risk if Python or asyncio internals shift.
License in practice
MIT license (permissive) imposes no restrictions on use, modification, or distribution in your own projects.
Quickstart
from syncer import sync
async def async_fun():
return 1
b = sync(async_fun) # convert to synchronous
result = b() # call synchronously
Verify before relying
- Whether the package works correctly with Python 3.12+ or newer asyncio implementations.
- Current state of the GitHub repository and whether maintainer is responsive to issues.
Package facts
| License | MIT (permissive) |
| Python support | not specified |
| Install friction | high — source build required |
| Runtime dependencies | none |
| Maintenance | dormant — 1,194 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 450,114/month — #6,593 on PyPI (30-day window, as of 2026-08-14) |
| Known vulnerabilities | none known (OSV.dev, checked 2026-08-14) |
Evidence: syncer-2.0.3.tar.gz
Keywords: syncer
Tags
More Testing packages
Pluggy provides a plugin system that lets you…
permissive · top 100 on PyPI
pytestpytest is a testing framework that lets you…
permissive · top 100 on PyPI
virtualenvvirtualenv creates isolated Python environments…
permissive · top 100 on PyPI
coverageCoverage.py measures which lines of Python code…
permissive · top 1,000 on PyPI
pytest-asynciopytest-asyncio is a pytest plugin that enables…
permissive · top 1,000 on PyPI
pytest-json-ctrfA pytest plugin that generates test reports in…
permissive · top 1,000 on PyPI
threadloopRuns Tornado coroutines from synchronous Python…
permissive · top 15,000 on PyPI
aiounittestProvides a test case class for writing unit…
permissive · top 15,000 on PyPI
async-stripeProvides an asynchronous wrapper around the…
permissive · top 15,000 on PyPI
asgirefProvides ASGI base libraries including…
permissive · top 1,000 on PyPI
synchronicityWraps async functions, generators, and classes…
permissive · top 1,000 on PyPI
async-propertyProvides Python decorators (@async_property and…
permissive · top 5,000 on PyPI
asyncio-atexitRegisters cleanup functions to run when an…
permissive · top 15,000 on PyPI
unsyncDecorator-based library that runs async…
permissive · top 15,000 on PyPI
aioprocessingProvides asyncio-compatible wrappers around…
permissive · top 15,000 on PyPI
asynctestExtends Python's unittest module with test…
permissive · top 5,000 on PyPI