<p align="center">
<a href="https://asyncer.tiangolo.com"><img src="https://asyncer.tiangolo.com/img/logo-margin/logo-margin-vector.svg" alt="Asyncer"></a>
</p>
<p align="center">
<em>Asyncer, async and await, focused on developer experience.</em>
</p>
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<img src="https://github.com/fastapi/asyncer/actions/workflows/test.yml/badge.svg?event=push&branch=main" alt="Test">
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<img src="https://coverage-badge.samuelcolvin.workers.dev/fastapi/asyncer.svg" alt="Coverage">
<a href="https://pypi.org/project/asyncer">
<img src="https://img.shields.io/pypi/v/asyncer?color=%2334D058&label=pypi%20package" alt="Package version">
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---
**Documentation**: [https://asyncer.tiangolo.com](https://asyncer.tiangolo.com)
**Source Code**: [https://github.com/fastapi/asyncer](https://github.com/fastapi/asyncer)
---
**Asyncer** is a small library built on top of [AnyIO](https://anyio.readthedocs.io/en/stable/).
**Asyncer** has a small number of utility functions that allow working with `async`, `await`, and concurrent code in a more convenient way under my ([@tiangolo - Sebastián Ramírez](https://twitter.com/tiangolo)) very opinionated and subjective point of view.
The main goal of **Asyncer** is to improve **developer experience** by providing better support for **autocompletion** and **inline errors** in the editor, and **more certainty** that the code is **bug-free** by providing better support for type checking tools like **mypy**.
**Asyncer** also tries to improve **convenience** and simplicity when working with **async** code **mixed** with regular <abbr title="synchronous code, code that is not async">**blocking code**</abbr>, allowing to use them together in a simpler way... again, under my very **subjective** point of view.
## Can I Use It?
Yes 🎉 (but continue reading).
This is a very small library, there are things that can change and improve in the future.
If you use it, **pin the exact Asyncer version** for your project, to make sure it all works.
Have **tests** for your project (as you should, anyway). And **upgrade the version** once you know that the new version continues to work correctly.
Still, it's **just 4 functions**, so there's not much to change, if you had to refactor your code to update something it would not be much.
And if you don't want to add `asyncer` as a dependency to your project, you can also just copy the main file and try out those functions, it's quite small (but in that case you won't get updates easily).
## Requirements
As **Asyncer** is based on **AnyIO** it will be also installed automatically when you install **Asyncer**.
## Installation
First, [install `uv`](https://docs.astral.sh/uv/getting-started/installation/), and then add Asyncer to your project:
<div class="termy">
```console
$ uv add asyncer
---> 100%
```
</div>
If you prefer to use `pip`, install `asyncer` inside a virtual environment. See the [installation guide](tutorial/install.md) for the alternative steps.
## How to Use
You can read more about each of the use cases and utility functions in **Asyncer** in the [tutorial](https://asyncer.tiangolo.com/tutorial/).
As a sneak preview of one of the utilities, you can **call sync code from async code** using `asyncify()`:
```Python
import time
import anyio
from asyncer import asyncify
def do_sync_work(name: str):
time.sleep(1)
return f"Hello, {name}"
async def main():
message = await asyncify(do_sync_work)(name="World")
print(message)
anyio.run(main)
```
**Asyncer**'s `asyncify()` will use AnyIO underneath to do *the smart thing*, avoid blocking the main **async** event loop, and run the **sync**/blocking function in a **worker thread**.
### Editor Support
Everything in **Asyncer** is designed to get the best **developer experience** possible, with the best editor support.
* **Autocompletion** for function arguments:
<img class="shadow" src="https://asyncer.tiangolo.com/img/tutorial/asyncify/image01.png">
* **Autocompletion** for return values:
<img class="shadow" src="https://asyncer.tiangolo.com/img/tutorial/asyncify/image02.png">
* **Inline errors** in editor:
<img class="shadow" src="https://asyncer.tiangolo.com/img/tutorial/soonify/image02.png">
* Support for tools like **mypy**, that can help you verify that your **code is correct**, and prevent many bugs.
## License
This project is licensed under the terms of the [MIT license](https://github.com/fastapi/asyncer/blob/main/LICENSE).