API reference

Features

Check which implementations support which features and known limitations.

asyncio

It’s ideal for servers that handle many clients concurrently.

This is the default implementation.

threading

This alternative implementation can be a good choice for clients.

Sans-I/O

This layer is designed for integrating in third-party libraries, typically application servers.

asyncio (legacy)

This is the historical implementation.

It is deprecated and will be removed.

Extensions

The Per-Message Deflate extension is built in. You may also define custom extensions.

Shared

These low-level APIs are shared by all implementations.

API stability

Public APIs documented in this API reference are subject to the backwards-compatibility policy.

Anything that isn’t listed in the API reference is a private API. There’s no guarantees of behavior or backwards-compatibility for private APIs.

Convenience imports

For convenience, some public APIs can be imported directly from the websockets package.