A Python 3.7+ server implementation of the JSON RPC 2.0 protocol. This library has been pulled out of the Python LSP Server project.
pip install -U python-lsp-jsonrpc
The examples directory contains two examples of running language servers over websockets. examples/langserver.py shows how to run a language server in-memory. examples/langserver_ext.py shows how to run a subprocess language server, in this case the Python LSP Server.
Start by installing tornado and python-lsp-server
pip install python-lsp-server[all] tornado
Then running python examples/langserver.py or python examples/langserver_ext.py will host a websocket on ws://localhost:3000/python.