PYSX — reactive interfaces in Python

PYSX is a server-side reactive UI library for Python. Build interfaces with indentation-based markup inside Python t-strings, keep state in signals, and send targeted updates to the browser when that state changes. Python handles user events on the server; a small JavaScript client applies the updates.

This extension provides editor support for the PYSX framework.

Install

Use Python 3.14 or newer. Install the framework and editor tooling in your project's Python environment:

python -m pip install 'pysx-framework[lsp,dev]==0.7.0'

Or, in a uv project:

uv add 'pysx-framework[lsp,dev]==0.7.0'

The lsp extra supplies the language server; dev supplies the pinned Ruff formatter. See the quickstart to run your first application.

VS Code support

Install PYSX (jmsapps.pysx) from the VS Code Marketplace. Select a Python 3.14 or later environment with PYSX and Ruff installed; the Python extension's selected interpreter is used unless pysx.pythonPath is set.

To build and install the same extension locally from the repository root:

./scripts/install-extension.sh
./scripts/uninstall-extension.sh

Either script changes the installed extension but not the running window, so run Developer: Reload Window afterwards.

The extension provides syntax highlighting for markup inside pysx(t"""...""") and advisory diagnostics for unknown component tags, unparenthesised lambdas, and called signals where a bare signal was intended.

Highlighting applies at literal call sites, including calls where a formatter puts the opening t-string on the next line. TextMate grammars do not follow variables or dataflow. Diagnostics refresh when a file opens or is saved, rather than as you type.

See the template grammar for authoring rules and verification setup for extension build and host tests.