BuiltWith Technology Profiler
Find out what the website you are visiting is built with using this extension.
Live HTTP Headers
Monitor all HTTP/HTTPs traffic from your browser.
Modify Header Value
Add, modify or remove a header for any request on desired domains.
Use Redux DevTools in the DevTools
Disable cookies for current domain.
View all HTTP Requests and Responses sent between the Web browser and the Web server.
Google Analytics Debugger
A browser extension for debugging Google Analytics tracking code
Browse JSON like you do it in Finder.
Picture in Play
Indicates whether the `picture` element is in use on a page.
Firebug Lite for Opera 15+
This extension allows you to add your own custom website specific CSS style sheets.
Quickly view the HTTP headers of the current tab.
Live editor for CSS and LESS - Magic CSS
Live preview of CSS/LESS code with an in-page editor. Autocomplete, convert LESS to CSS, beautify, minify, CSS reloader, linter, ...
Remove cookie(s) for the current domain
Remove cookie(s) for the current site with just one click
Get Thumbnails or Image to video YouTube
Make thumbnail previews or images from YouTube videos
Edit the Page
Toggles the 'Design Mode' so that you can edit the contents of the page.
Website Analysis & SEO Tool
Website SEO audit tool that provides website analysis in SEO, performance, validity, security, accessibility and other criteria.
Right Click Validator
Right click on any webpage to validate it using the W3 NUValidator service.
WordPress Theme and Plugins Detector
This tool detects theme and plugins used on WordPress sites and displays information about them.
Browserling - Cross-browser testing
Cross-browser test websites in the most popular browsers such as Internet Explorer, Edge, Chrome, Firefox, Safari and Opera. Try for free!
Edit with Adobe Photoshop
Adds a context menu item to send image links directly to Adobe Photoshop photo editor
A small extension to validate the markup of current tab
Website Color Changer
Extends the Developer Tools, adding a sidebar for colors manipulation
This extension predicts rating changes for Codeforces. It shows approximate deltas during and after the contest.
An extention to show/inspect and analyze fonts in web-pages.
SEO Analysis with Seoptimer
Just one click to SEO Analysis with Seoptimer
OCR - Image Reader
A powerful optical character recognition (OCR) extension to capture and convert images to text
Shows the response times and uptime of a desired server. Useful to see how performs internet or a wireless access point.