Userscript Core

Shared runtime, utilities and build tooling for every userscript in this repository. Write features, not plumbing.

What you get#

• A Userscript runtime with a feature registry, mutation-driven updates, navigation events and a command registry.
• A Feature base class with enable/disable hooks and automatic cleanup.
• Storage, logger, DOM helpers, waiting, HTTP, menu sync, style injection and a page fetch observer.
• A build helper that generates the metadata header and bundles the script.

This is a library. It is bundled into each userscript and is not installed on its own.

Quick start#

bun scripts/new-userscript.ts my-script "My Script"

Then read Getting started and the API reference.