Sanic

25.12.0 · active · verified Fri Apr 10

Sanic is an asynchronous Python 3.10+ web server and web framework designed for high performance. It leverages Python's `async/await` syntax and optionally `uvloop` for blazing-fast I/O. Sanic is ASGI compliant, allowing flexible deployment, and offers a Flask-like API for rapid development. The project is actively maintained by the community, with a frequent release cadence, often monthly, following a YY.MM.PATCH versioning scheme. The current version is 25.12.0.

Warnings

breaking Sanic requires explicit response objects (e.g., `text()`, `json()`). Unlike frameworks like Flask, returning raw strings or dictionaries from handlers is not supported and will result in errors, as Sanic aims to avoid implicit conversions for performance.
Fix: Always wrap your return values in a `sanic.response` object, such as `text()`, `json()`, `html()`, or `file()`.
breaking The functionality and parsing of `Request.accept` changed significantly. Relying on its equality operations may produce incorrect results. The `match()` method is now the preferred way to interact with `Request.accept`.
Fix: Transition to using `request.accept.match()` for content type negotiation.
breaking Response cookies are no longer dict-like objects. Direct dictionary methods (e.g., `cookie['key'] = value`) for `response.cookies` were removed.
Fix: Access and manipulate response cookies using object-oriented methods (e.g., `response.cookies['key']`, `del response.cookies['key']`) rather than dictionary-specific methods (like `.update()` or `.items()`).
breaking Duplicate route names are no longer allowed. Registering multiple routes with the same name will raise a `sanic.exceptions.ServerError`.
Fix: Ensure all routes have unique names. You can explicitly set a name using the `name` parameter in the `@app.route()` decorator or by ensuring function/class names are unique.
deprecated The `sanic.worker.GunicornWorker` class has been removed. Running Sanic with Gunicorn should now be done via `uvicorn` as an ASGI application.
Fix: Migrate Gunicorn deployments to use Uvicorn for serving Sanic applications. Refer to Uvicorn's documentation for integration with Gunicorn.
gotcha `uvloop` is Unix-specific. If `uvloop` is enabled (which is the default on supported platforms), Sanic applications may not run or perform optimally on Windows. You can explicitly disable `uvloop` via an environment variable.
Fix: On Windows, either set `SANIC_NO_UVLOOP=true` before installing/running, or use a Linux-based environment (e.g., WSL, Docker) for development and deployment.

Install

pip install sanic Base Install
pip install "sanic[ext]" Install with Sanic Extensions

Imports

Sanic
```
from sanic import Sanic
```
Response types
```
from sanic.response import text, json
```
Sanic requires explicit response objects (e.g., `text()`, `json()`) unlike some other frameworks that implicitly convert return values.
Request
```
async def handler(request: Request):
```
The `request` object is always passed as the first argument to route handlers, not accessed via a global context variable.

Quickstart

This minimal Sanic application defines a single GET route at the root path ('/') that returns 'Hello, world.' It demonstrates app initialization, route decoration, explicit asynchronous handler definition, and using a Sanic response object. Run with `python your_app.py` or `sanic your_app:app --debug`.

from sanic import Sanic
from sanic.response import text

app = Sanic("MyHelloWorldApp")

@app.get("/")
async def hello_world(request):
    return text("Hello, world.")

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=8000, debug=True)

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