---
id: comm
version: "0.2.3"
license: BSD 3-Clause License Copyright (c) 2022, Jupyter All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following… (full text in the JSON record)
license_treatment: permissive
maintenance: aging
---

# comm — Jupyter Python Comm implementation, for usage in ipykernel, xeus-python etc.

License: permissive · Maintenance: aging · Popularity: top 1,000 on PyPI

## Install

pip install comm
uv add comm
poetry add comm

## Description

# Comm

It provides a way to register a Kernel Comm implementation, as per the Jupyter kernel protocol.
It also provides a base Comm implementation and a default CommManager that can be used.

## Register a comm implementation in the kernel:

### Case 1: Using the default CommManager and the BaseComm implementations

We provide default implementations for usage in IPython:

```python
import comm


class MyCustomComm(comm.base_comm.BaseComm):
    def publish_msg(self, msg_type, data=None, metadata=None, buffers=None, **keys):
        # TODO implement the logic for sending comm messages through the iopub channel
        pass


comm.create_comm = MyCustomComm
```

This is typically what ipykernel and JupyterLite's pyolite kernel will do.

### Case 2: Providing your own comm manager creation implementation

```python
import comm

comm.create_comm = custom_create_comm
comm.get_comm_manager = custom_comm_manager_getter
```

This is typically what xeus-python does (it has its own manager implementation using xeus's C++ messaging logic).

## Comm users

Libraries like ipywidgets can then use the comms implementation that has been registered by the kernel:

```python
from comm import...

## AI interpretation — verify before relying

Comm provides a Jupyter kernel protocol implementation for registering and managing inter-process communication (comms) between kernels and frontends, enabling libraries like ipywidgets to send messages through a standardized interface.

Verdict: Comm is a lightweight, well-maintained foundational library for Jupyter kernel communication with permissive licensing and no external dependencies. Its aging release cadence is typical for stable infrastructure; it remains actively supported and is essential for Jupyter-based interactive computing stacks. Suitable for production use in Jupyter environments.

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