Disable cookies for current domain.
Right Click Validator
Right click on any webpage to validate it using the W3 NUValidator service.
Live HTTP Headers
Monitor all HTTP/HTTPs traffic from your browser.
Use Redux DevTools in the DevTools
Firebug Lite for Opera 15+
GitHub code tree on steroids
Определение CMS - iTrack
Расширение для определения CMS сайта
Click on any HTML element to get the font info in a popup
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, ...
PDF API HTML5
Modify Header Value
Add, modify or remove a header for any request on desired domains.
Website Analysis & SEO Tool
Website SEO audit tool that provides website analysis in SEO, performance, validity, security, accessibility and other criteria.
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!
SEO Analysis with Seoptimer
Just one click to SEO Analysis with Seoptimer
Browse JSON like you do it in Finder.
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.
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
A webpage form filler that populates context specific random test data into forms elements.
Web Developer Checklist
Analyses any web page for violations of best practices
Website Color Changer
Extends the Developer Tools, adding a sidebar for colors manipulation
Shows the response times and uptime of a desired server. Useful to see how performs internet or a wireless access point.
WordPress Theme and Plugins Detector
This tool detects theme and plugins used on WordPress sites and displays information about them.
Edit with Adobe Photoshop
Adds a context menu item to send image links directly to Adobe Photoshop photo editor
Remove cookie(s) for the current domain
Remove cookie(s) for the current site with just one click
Google Analytics Debugger
A browser extension for debugging Google Analytics tracking code
Wayback machine website
Online service that have 452 billion web pages saved over time and who is domain tool in context menu
Quickly view the HTTP headers of the current tab.
Fast balance viewer for your affiliate networks and partner programs