Browser extensions provide a convenient and powerful way for people to take control of how they experience the web. From blocking ads to organizing tabs, extensions let people solve everyday problems and add whimsy to their online lives.

At yesterday’s WWDC event, Apple announced that Safari is adopting a web-based API for browser extensions similar to Firefox’s WebExtensions API. Built using familiar web technologies such as JavaScript, HTML, and CSS, the API makes it easy for developers to write one code base that will work in Firefox, Chrome, Opera, and Edge with minimal browser-specific changes. We’re excited to see expanded support for this common set of browser extension APIs.

What this means for you

Interested in porting your browser extension to Safari? Visit MDN to see which APIs are currently supported. Developers can start testing the new API in Safari 14 using the seed build for macOS Big Sur. The API will be available in Safari 14 on macOS Mojave and macOS Catalina in the future.

Or, maybe you’re new to browser extension development. Check out our guides and tutorials to learn more about the WebExtensions API. Then, visit Firefox Extension Workshop to find information about development tools, security best practices, and tips for creating a great user experience. Be sure to take a look at our guide for how to build a cross-browser extension.

Ready to share your extension with the world (or even just a few friends!)? Our documentation will guide you through the process of making your extension available for Firefox users.

Happy developing!