A set of tools for inspecting and editing web code.
Our team works closely with the community and is always happy to
welcome new contributors.
Get InvolvedHelp build the last independent browser. Write code, fix bugs, make add-ons, and more.
Speak UpFeedback makes us better. Tell us how we can improve the browser and Developer tools.
Inspect and refine code to build pixel-perfect layouts.
Monitor network requests that can slow or block your site.
Add, modify and remove cache, cookies, databases and session data.
Test sites on emulated devices in your browser.
Fine-tune animations, alignment and padding.
Unblock bottlenecks, streamline processes, optimize assets.
Find memory leaks and make your application zippy.