To use Android extensions, you'll need Firefox for Android. To explore Firefox for desktop add-ons, please visit our desktop site.
Inspect image dimensions format and metadata instantly
Store Wi-Fi network names and passwords locally in an encrypted vault
On-screen ruler to measure distances and element sizes in pixels
Read and display image metadata from uploaded photo files
Persistent markdown notebook with live preview toggle
Overlay ruler tool to check sizes and spacing on page
Save text templates with placeholders and autofill any text field on click
Drop in your RSS feeds and read latest headlines from the toolbar
Query CSS selectors by clicking elements on any webpage
Preview how any page looks when shared on Twitter, Facebook and LinkedIn
Speed up form filling — store profiles and inject them into web forms
Inspect and copy CSS variables used on any website
View, edit and delete localStorage and sessionStorage for any page
JSON viewer for raw API responses — formatted, searchable and copy-ready
Fast markdown notepad with formatting and storage
Decode and inspect JWT tokens with header payload and exp
Click any element to get its CSS selector and copy it
Deep work timer — block chosen sites and track focus sessions
Real-time cursor position tracker with viewport metrics
Override any site's CSS with your own rules — saved per domain
Zap fixed-position banners, cookie bars and sticky headers instantly
Map every image on the current page — dimensions, alt and URL
List all images on the page with size, alt text and source URL
Sniff the tech stack — detect React, Vue, WordPress, jQuery and 30+ more
