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A language server for Jedi!

Project description


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A Language Server for the latest version(s) of Jedi. If using Neovim/Vim, we recommend using with coc-jedi. Supports Python versions 3.6 and newer.

Note: this tool is actively used by its primary author. He's happy to review pull requests / respond to issues you may discover.


Some frameworks, like coc-jedi and vscode-python, will install and manage jedi-language-server for you. If you're setting up manually, you can run the following from your command line (bash / zsh):

pip install -U jedi-language-server

Alternatively (and preferably), use pipx to keep jedi-language-server and its dependencies isolated from your other Python dependencies. Don't worry, jedi is smart enough to figure out which Virtual environment you're currently using!


jedi-language-server aims to support Jedi's capabilities and expose them through the Language Server Protocol. It supports the following Language Server capabilities:

Language Features

Text Synchronization (for diagnostics)

Editor Setup

The following instructions show how to use jedi-language-server with your development tooling. The instructions assume you have already installed jedi-language-server.

Vim / Neovim

Users may choose 1 of the following options:

Note: this list is non-exhaustive. If you know of a great choice not included in this list, please submit a PR!


Users may choose one of the following options:

For eglot add the following to your emacs config:

(add-to-list 'eglot-server-programs '(python-mode . ("jedi-language-server")))

Note: this list is non-exhaustive. If you know of a great choice not included in this list, please submit a PR!

Visual Studio Code (vscode)

Starting from the October 2021 release, set the python.languageServer setting to Jedi to use jedi-language-server.

Note: This does not support Python 2.7.


Command line

jedi-language-server can be run directly from the command line.

$ jedi-language-server --help
usage: jedi-language-server [-h] [--version] [--tcp] [--ws] [--host HOST] [--port PORT] [--log-file LOG_FILE] [-v]

Jedi language server: an LSP wrapper for jedi.

optional arguments:
  -h, --help           show this help message and exit
  --version            display version information and exit
  --tcp                use TCP web server instead of stdio
  --ws                 use web socket server instead of stdio
  --host HOST          host for web server (default
  --port PORT          port for web server (default 2087)
  --log-file LOG_FILE  redirect logs to file specified
  -v, --verbose        increase verbosity of log output


    Run over stdio     : jedi-language-server
    Run over tcp       : jedi-language-server --tcp
    Run over websockets:
        # only need to pip install once per env
        pip install pygls[ws]
        jedi-language-server --ws


    For use with web sockets, user must first run
    'pip install pygls[ws]' to install the correct
    version of the websockets library.

If testing sending requests over stdio manually from the command line, you must include Windows-style line endings: \r\n . For an example, from within this project, run the following:

$ jedi-language-server < ./example-initialization-request.txt
INFO:pygls.server:Starting IO server
INFO:pygls.feature_manager:Registered "textDocument/didOpen" with options "None"
INFO:pygls.feature_manager:Registered "textDocument/didChange" with options "None"
INFO:pygls.feature_manager:Registered "textDocument/didSave" with options "None"
INFO:pygls.feature_manager:Registered "textDocument/hover" with options "None"
INFO:pygls.protocol:Language server initialized work_done_token=None process_id=None root_uri='file:///home/ubuntu/artifacts/' capabilities=ClientCapabilities(workspace=WorkspaceClientCapabilities(apply_edit=None, workspace_edit=None, did_change_configuration=DidChangeConfigurationClientCapabilities(dynamic_registration=True), did_change_watched_files=None, symbol=None, execute_command=None, workspace_folders=None, configuration=None, semantic_tokens=None, code_lens=None, file_operations=None), text_document=TextDocumentClientCapabilities(synchronization=TextDocumentSyncClientCapabilities(dynamic_registration=True, will_save=False, will_save_wait_until=False, did_save=False), completion=CompletionClientCapabilities(dynamic_registration=True, completion_item=CompletionItemClientCapabilities(snippet_support=False, commit_characters_support=True, documentation_format=[<MarkupKind.PlainText: 'plaintext'>, <MarkupKind.Markdown: 'markdown'>], deprecated_support=False, preselect_support=False, tag_support=None, insert_replace_support=None, resolve_support=None, insert_text_mode_support=None), completion_item_kind=None, context_support=False), hover=HoverClientCapabilities(dynamic_registration=True, content_format=[<MarkupKind.PlainText: 'plaintext'>, <MarkupKind.Markdown: 'markdown'>]), signature_help=SignatureHelpClientCapabilities(dynamic_registration=True, signature_information=SignatureHelpInformationClientCapabilities(documentation_format=[<MarkupKind.PlainText: 'plaintext'>, <MarkupKind.Markdown: 'markdown'>], parameter_information=None, active_parameter_support=None), context_support=None), declaration=DeclarationClientCapabilities(dynamic_registration=True, link_support=True), definition=DefinitionClientCapabilities(dynamic_registration=True, link_support=True), type_definition=TypeDefinitionClientCapabilities(dynamic_registration=True, link_support=True), implementation=ImplementationClientCapabilities(dynamic_registration=True, link_support=True), references=None, document_highlight=None, document_symbol=None, code_action=None, code_lens=None, document_link=None, color_provider=None, formatting=None, range_formatting=None, on_type_formatting=None, rename=None, publish_diagnostics=None, folding_range=None, selection_range=None, linked_editing_range=None, call_hierarchy=None, semantic_tokens=None, moniker=None), window=None, general=None, experimental=None) client_info=None locale=None root_path=None initialization_options=None trace=None workspace_folders=None
INFO:pygls.protocol:Sending data: {"jsonrpc": "2.0", "id": 0, "result": {"capabilities": {"textDocumentSync": {"openClose": true, "change": 2, "willSave": false, "willSaveWaitUntil": false, "save": true}, "completionProvider": {"triggerCharacters": [".", "'", "\""], "resolveProvider": true}, "hoverProvider": true, "signatureHelpProvider": {"triggerCharacters": ["(", ","]}, "definitionProvider": true, "referencesProvider": true, "documentHighlightProvider": true, "documentSymbolProvider": true, "codeActionProvider": {"codeActionKinds": ["refactor.inline", "refactor.extract"]}, "renameProvider": true, "executeCommandProvider": {"commands": []}, "workspaceSymbolProvider": true, "workspace": {"workspaceFolders": {"supported": true, "changeNotifications": true}, "fileOperations": {}}}}}
Content-Length: 758
Content-Type: application/vscode-jsonrpc; charset=utf-8

{"jsonrpc": "2.0", "id": 0, "result": {"capabilities": {"textDocumentSync": {"openClose": true, "change": 2, "willSave": false, "willSaveWaitUntil": false, "save": true}, "completionProvider": {"triggerCharacters": [".", "'", "\""], "resolveProvider": true}, "hoverProvider": true, "signatureHelpProvider": {"triggerCharacters": ["(", ","]}, "definitionProvider": true, "referencesProvider": true, "documentHighlightProvider": true, "documentSymbolProvider": true, "codeActionProvider": {"codeActionKinds": ["refactor.inline", "refactor.extract"]}, "renameProvider": true, "executeCommandProvider": {"commands": []}, "workspaceSymbolProvider": true, "workspace": {"workspaceFolders": {"supported": true, "changeNotifications": true}, "fileOperations": {}}}}}INFO:pygls.server:Shutting down the server
INFO:pygls.server:Closing the event loop.

If testing interactively, be sure to manually insert carriage returns. Although this may differ between shell environments, within most bash terminals, you can explicitly insert the required line endings by typing <C-v><C-m>, which will insert a ^M. See:

$ jedi-language-server 2>logs
Content-Length: 1062^M
Content-Length: 758
Content-Type: application/vscode-jsonrpc; charset=utf-8

{"jsonrpc": "2.0", "id": 0, "result": {"capabilities": {"textDocumentSync": {"openClose": true, "change": 2, "willSave": false, "willSaveWaitUntil": false, "save": true}, "completionProvider": {"triggerCharacters": [".", "'", "\""], "resolveProvider": true}, "hoverProvider": true, "signatureHelpProvider": {"triggerCharacters": ["(", ","]}, "definitionProvider": true, "referencesProvider": true, "documentHighlightProvider": true, "documentSymbolProvider": true, "codeActionProvider": {"codeActionKinds": ["refactor.inline", "refactor.extract"]}, "renameProvider": true, "executeCommandProvider": {"commands": []}, "workspaceSymbolProvider": true, "workspace": {"workspaceFolders": {"supported": true, "changeNotifications": true}, "fileOperations": {}}}}}


We recommend using coc-jedi and following its configuration instructions.

If you are configuring manually, jedi-language-server supports the following initializationOptions:

  "initializationOptions": {
    "codeAction": {
      "nameExtractVariable": "jls_extract_var",
      "nameExtractFunction": "jls_extract_def"
    "completion": {
      "disableSnippets": false,
      "resolveEagerly": false,
      "ignorePatterns": []
    "diagnostics": {
      "enable": true,
      "didOpen": true,
      "didChange": true,
      "didSave": true
    "hover": {
      "enable": true,
      "disable": {
        "class": { "all": false, "names": [], "fullNames": [] },
        "function": { "all": false, "names": [], "fullNames": [] },
        "instance": { "all": false, "names": [], "fullNames": [] },
        "keyword": { "all": false, "names": [], "fullNames": [] },
        "module": { "all": false, "names": [], "fullNames": [] },
        "param": { "all": false, "names": [], "fullNames": [] },
        "path": { "all": false, "names": [], "fullNames": [] },
        "property": { "all": false, "names": [], "fullNames": [] },
        "statement": { "all": false, "names": [], "fullNames": [] }
    "jediSettings": {
      "autoImportModules": [],
      "caseInsensitiveCompletion": true,
      "debug": false
    "markupKindPreferred": "markdown",
    "workspace": {
      "extraPaths": [],
      "symbols": {
        "ignoreFolders": [".nox", ".tox", ".venv", "__pycache__", "venv"],
        "maxSymbols": 20

See coc-jedi's configuration instructions for an explanation of the above configurations.

Additional Diagnostics

jedi-langugage-server provides diagnostics about syntax errors, powered by Jedi. If you would like additional diagnostics, we suggest using the powerful diagnostic-language-server.

Code Formatting

Again, we recommend that you use diagnostic-language-server. It also supports code formatting.

Local Development

To build and run this project from source:


Install the following tools manually:


Get source code

Fork this repository and clone the fork to your development machine:

git clone<YOUR-USERNAME>/jedi-language-server
cd jedi-language-server

Set up development environment

make setup

Run tests

make test


Palantir's python-language-server inspired this project. In fact, for consistency's sake, many of python-language-server's CLI options are used as-is in jedi-language-server.

Unlike python-language-server, jedi-language-server:

  • Uses pygls instead of creating its own low-level Language Server Protocol bindings
  • Supports one powerful 3rd party static analysis / completion / refactoring library: Jedi. By only supporting Jedi, we can focus on supporting all Jedi features without exposing ourselves to too many broken 3rd party dependencies (I'm looking at you, rope).
  • Is supremely simple because of its scope constraints. Leave complexity to the Jedi master. If the force is strong with you, please submit a PR!


Written by

Samuel Roeca

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