jupyterlab-lsp

library5.3.0pypypiunverified

jupyterlab-lsp integrates Language Server Protocol (LSP) features directly into JupyterLab, providing coding assistance like autocompletion, hover documentation, linting, and refactoring. As of version 5.3.0, it supports JupyterLab 4.x and is actively maintained with regular updates focusing on compatibility and new LSP features.

devops data

pip install jupyterlab-lsp

github ↗package ↗docs ↗

INSTALL

IMPORT

SIG · JUPYTERLAB-LSP

jupyterlab-lsp

devopspythonv5.3.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

This Python code, when opened in a `.py` file or a notebook within JupyterLab (after `jupyterlab-lsp` and `python-lsp-server` are installed), will demonstrate LSP features. You'll see type hints, signature help, hover documentation, and autocompletion provided by the extension.

# hello_lsp.py import os def greet(name: str) -> str: """ Returns a greeting message. Hover over 'greet' for documentation. Type 'greet(' to see signature help. """ message = f"Hello, {name}!" # Type 'message.' to trigger autocompletion provided by LSP return message.upper() if __name__ == '__main__': user_name = os.environ.get('USER_NAME', 'World') print(greet(user_name))

Debug

Known issues

breakingMajor versions of `jupyterlab-lsp` are tightly coupled to major versions of `JupyterLab`. For example, `jupyterlab-lsp` 4.x is for `JupyterLab` 4.x, and `jupyterlab-lsp` 3.x is for `JupyterLab` 3.x. Installing an incompatible version can lead to errors or the extension not loading.

fix

Ensure your `jupyterlab-lsp` version matches your `JupyterLab` major version. Upgrade both simultaneously or check the compatibility matrix on the official GitHub page.

affects: All major versions (e.g., 3.x.x for JL3, 4.x.x for JL4, 5.x.x for JL4)

gotchaAfter installing `jupyterlab-lsp`, users often expect immediate coding assistance for all languages. However, `jupyterlab-lsp` itself only provides the framework; each language (e.g., Python, R, TypeScript) requires its own specific language server to be installed separately.

fix

Install the appropriate language server for your desired language. For Python, `pip install 'python-lsp-server[all]'` is commonly used. For other languages, consult the `jupyterlab-lsp` documentation.

affects: All versions

gotchaSometimes, after installing or upgrading `jupyterlab-lsp` or other JupyterLab extensions, the frontend assets might become stale or cached incorrectly, leading to features not appearing or errors in the browser console.

fix

Try running `jupyter lab build` in your terminal to rebuild the frontend assets. Additionally, clear your browser cache (Ctrl+Shift+R or Cmd+Shift+R) and restart your JupyterLab server.

affects: All versions

Errors

Common errors & fixes

Language Server not found: python

The Python language server (e.g., `python-lsp-server`) is not installed or not discoverable by `jupyterlab-lsp`.

fix

Install the `python-lsp-server` package in the same environment as JupyterLab: `pip install 'python-lsp-server[all]'`.

Uncaught (in promise) Error: 404 Not Found

This error often indicates a problem with the JupyterLab server extension not being loaded correctly, an outdated frontend build, or an incorrect path for server components.

fix

First, try rebuilding JupyterLab assets: `jupyter lab build`. If the issue persists, verify that `jupyterlab-lsp` is enabled (`jupyter labextension list` and `jupyter server extension list`) and restart your JupyterLab server. Clear your browser cache.

ModuleNotFoundError: No module named 'jupyterlab_lsp'

The `jupyterlab-lsp` Python package is not installed in the active Python environment where JupyterLab is running.

fix

Install the package: `pip install jupyterlab-lsp`.

Upgrade

Version history

5.3.0latest on PyPI · released Apr 2, 2026

Audit

Dependencies

jupyterlabrequiredCore JupyterLab environment for the extension to run in.

python-lsp-serveroptionalProvides Python-specific language server features (e.g., autocompletion, linting). Required for Python language support; other language servers are needed for different languages.

Agent activity

2 hits · last 30 days

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Resources

githubhttps://github.com/jupyter-lsp/jupyterlab-lsp ↗

packagehttps://pypi.org/project/jupyterlab-lsp/ ↗

docshttps://jupyterlab-lsp.readthedocs.io/ ↗