---
id: pyviz-comms
version: "3.0.6"
license: BSD 3-Clause License Copyright (c) 2023, Philipp Rudiger All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the… (full text in the JSON record)
license_treatment: permissive
maintenance: active
---

# pyviz-comms — A JupyterLab extension for rendering HoloViz content.

License: permissive · Maintenance: active · Downloads: 2.3M/mo

## What it is and what it does

pyviz_comms is a communication bridge for Jupyter environments that allows Python code running in the kernel to exchange messages with JavaScript code in the browser frontend. It abstracts away the complexity of Jupyter's comm protocol, providing a simple API for bidirectional messaging. The package is designed primarily to support HoloViz visualization tools (like HoloViews, Panel, and Datashader) in rendering interactive plots and dashboards, though it can be used by any tool that needs kernel-frontend communication.

The package consists of a Python component and an optional JupyterLab extension. For JupyterLab 3.0 and later, the extension is automatically included when you install the Python package via pip or conda. The package supports modern Python versions (3.8 through 3.11) and is actively maintained with a stable, production-ready status.

Use it for:

- Building interactive HoloViz visualizations that respond to user input in Jupyter notebooks and JupyterLab.
- Enabling real-time communication between Python analysis code and browser-based UI components in Panel dashboards.
- Creating custom Jupyter extensions that need to exchange data between kernel and frontend without writing low-level comm protocol code.
- Supporting collaborative visualization tools where Python computations drive live JavaScript rendering.
- Integrating third-party JavaScript libraries with Python-based Jupyter workflows via message passing.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Provides bidirectional communication between Python and JavaScript in Jupyter notebooks and JupyterLab, enabling HoloViz tools to send and receive messages across the kernel-frontend boundary.

Yes. Install if you're building or using HoloViz tools in Jupyter, or if you need a straightforward way to add bidirectional Python-JavaScript communication to a Jupyter extension. The package is low-friction, actively maintained, permissively licensed, and has no known vulnerabilities. It's a stable dependency for interactive visualization workflows.

## Install

pip install pyviz-comms
uv add pyviz-comms
poetry add pyviz-comms

## Installing pyviz-comms

Before you install: Low friction: pure Python wheel with a single dependency (param). Actively maintained with recent commits and stable status. Automatically bundled with JupyterLab 3.0+.

License in practice: BSD 3-Clause License permits commercial and private use with minimal restrictions; you must retain copyright notice and disclaimer in distributions.

Quickstart:

pip install pyviz_comms

from pyviz_comms import Comm
comm = Comm(target_name='my_target')

JupyterLab 3.0+ includes the extension automatically; older JupyterLab versions require separate manual extension installation.

Verify before relying:

- Whether the package works with non-Jupyter Python environments or is strictly Jupyter-dependent.
- Performance characteristics or message throughput limits for high-frequency communication scenarios.
- Specific HoloViz tool version requirements beyond the general compatibility table provided.

## Package facts

- License: BSD 3-Clause License Copyright (c) 2023, Philipp Rudiger All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the… (full text in the JSON record) (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 2.3M/month (top 5,000 on PyPI)
- Known vulnerabilities: none known

## Tags

jupyter python javascript communication, jupyterlab extension holoviz, bidirectional comms jupyter, holoviz interactive visualization, jupyter kernel frontend messaging, jupyterlab pyviz extension, interactive notebook communication, jupyter-extension, holoviz-ecosystem, interactive-viz

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