A set of core libraries and tools for building web extensions. These libraries are built on top of webextension-polyfill and support all major browsers.

• A lightweight, type-safe wrapper around the messaging API
• Local storage based, type-safe wrappers around the storage API
• An in-memory implementation of the Browser APIs for testing
• Write services that can be called from any JS context, but run in the background service worker
• Isolate content script UIs from the page's styles

See packages/<package-name>/README.md for more details about the individual packages.

• @webext-core/content-script-ctx: Stop content scripts when their context is invalidated
• @webext-core/publish: A tool for publishing an extension to the various stores

To use an NPM module in a web extension, you'll need to install a bundler and configure it for web extensions. Then install any of the packages from the @webext-core scope:

# Install a bundler and plugin for building extensions
npm i -D vite vite-plugin-web-extension

# Install a @webext-core package
npm i @webext-core/messaging
npm i @webext-core/storage
npm i -D @webext-core/publish