belgie 0.27.1

A minimal, secure javascript runtime for python

Belgie: A secure JavaScript runtime for Python, powered by Deno

Belgie lets you run JavaScript and TypeScript from Python. Deno is bundled — you do not need Node.js or Deno on your PATH.

• Scripts from Python: Run inline or file-based JS/TS with Runtime and Script, sync or async.
• Inline dependencies: Import npm, JSR, and URL modules directly from JS/TS source.
• Isolated packages: Use Environment for lockfiles, custom cache/options, local packages, and commands.
• CLI tools: Run npm binaries (Vite, esbuild, etc.) through Command.
• Simple data bridge: Pass JSON-safe dicts, lists, and primitives across the boundary.

Installation

uv add belgie
uvx library-skills install  # optional: install the use-belgie skill for Cursor, Codex, Claude, etc.

uv add belgie adds the library (Python >=3.12,<3.15, no runtime Python deps).

uvx library-skills install is optional. It links the bundled use-belgie agent skill into .agents/skills/ so coding agents can follow belgie's public API when you work on integrations. Skip it if you only need the Python library.

Quick Start

import asyncio

from belgie import Runtime, Script

script = Script(
    """
import camelcase from "npm:camelcase@8.0.0";

export default function run(input) {
  return camelcase(input);
}
"""
)

async def main() -> None:
    async with Runtime() as run:
        print(await run(script)("foo-bar"))  # prints: fooBar

asyncio.run(main())

Examples

• simple: Async Runtime with a TypeScript file on disk.
• inline-deps: Direct npm:, jsr:, and URL imports in a script.
• jsr-deps: JSR packages declared through an explicit Environment.
• environment: Sync and async Environment setup with path.
• commands: npm package binaries via Runtime and Command.

For deeper integration guidance, optionally install the use-belgie skill with uvx library-skills install.