Disable cookies for current domain.
Use Redux DevTools in the DevTools
PDF API HTML5
Live HTTP Headers
Monitor all HTTP/HTTPs traffic from your browser.
Firebug Lite for Opera 15+
Click on any HTML element to get the font info in a popup
View all HTTP Requests and Responses sent between the Web browser and the Web server.
Edit the Page
Toggles the 'Design Mode' so that you can edit the contents of the page.
This extension allows you to add your own custom website specific CSS style sheets.
Browse JSON like you do it in Finder.
Corser - Authorize CORS requests
Cross-browser extension for authorizing cross-origin resource sharing (CORS) requests. This extension can be installed on browsers supporting the WebExtensions API (https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions) It intercepts all CORS requests and responses headers, and records/adds/changes their values so as to authorized unauthorized CORS requests. Use this extension only for testing purposes
Quickly view the HTTP headers of the current tab.
Picture in Play
Indicates whether the `picture` element is in use on a page.
Get Thumbnails or Image to video YouTube
Make thumbnail previews or images from YouTube videos
Edit with Adobe Photoshop
Adds a context menu item to send image links directly to Adobe Photoshop photo editor
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!
This will take the URL of the current tab and send it to PageSpeed Insights for a web performance analysis.
This extension predicts rating changes for Codeforces. It shows approximate deltas during and after the contest.
Website Color Changer
Extends the Developer Tools, adding a sidebar for colors manipulation
ChroPath for Opera
AutonomIQ offers a developers platform ChroPath to generate and validate unique selectors like relative xpath with iframe support
Google Analytics Debugger
A browser extension for debugging Google Analytics tracking code
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, ...
A webpage form filler that populates context specific random test data into forms elements.
Open in Vivaldi
Open current page, link, or all tabs in the Vivaldi browser.
Remove cookie(s) for the current domain
Remove cookie(s) for the current site with just one click
SEO Analysis with Seoptimer
Just one click to SEO Analysis with Seoptimer
Website Analysis & SEO Tool
Website SEO audit tool that provides website analysis in SEO, performance, validity, security, accessibility and other criteria.