Python Language Server

0.36.2 verified Fri May 01 auth: no python deprecated

An implementation of the Language Server Protocol (LSP) for Python. Version 0.36.2 is the final release; the project is deprecated in favor of python-lsp-server (a community fork) and pyright/pylance. It provides IDE features like autocompletion, linting, code navigation, and refactoring.

pip install python-language-server

Common errors

error ModuleNotFoundError: No module named 'pyls' ↓

cause The package is installed but not in the current Python environment, or the wrong import name is used.

fix

Ensure the package is installed: pip install python-language-server. Then import as import pyls.

error AttributeError: module 'pyls' has no attribute 'ProcessServer' ↓

cause Using an older version of pyls that lacks the ProcessServer class (introduced in 0.36.0).

fix

Upgrade to the latest version: pip install --upgrade python-language-server.

error Error: No configuration found for 'pyls' ↓

cause Configuration file is missing or uses an outdated format.

fix

Create a .pylsrc file in the project root or home directory. See https://github.com/palantir/python-language-server#configuration

Warnings

deprecated python-language-server is deprecated. The Palantir project has been archived and no longer maintained. Users should migrate to python-lsp-server (community fork) or pyright/pylance. ↓

fix Replace python-language-server with python-lsp-server: `pip install python-lsp-server` and change imports to `import pylsp`.

breaking In version 0.36.0, the configuration format changed. Options that were previously under 'pyls' section are now under the tool's name (e.g., 'pyls.plugins' moved to 'pyls.plugins.jedi' etc.). ↓

fix Update your .pylsrc or editor settings to match the new schema. See: https://github.com/palantir/python-language-server/releases/tag/0.36.0

gotcha The package name on PyPI is python-language-server, but the import module is 'pyls'. Many users mistakenly try `import python_language_server` or `import pyls` with wrong casing. ↓

fix Use `import pyls` (all lowercase).

Imports

pyls
wrong
```
from pyls import server
```
correct
```
import pyls
```
The main entry point is the `pyls` module; direct imports of internal submodules are unsupported.

Quickstart

Basic usage: the server is typically started by an editor plugin. The `pyls` module provides a `ProcessServer` class for programmatic launching.

# Start the language server (usually launched by an editor plugin)
# For manual testing, run:
# pyls

# In code, you can invoke the server programmatically:
import pyls
server = pyls.ProcessServer()
print("Python Language Server started. Use an LSP client to connect.")