Sim Daltonism

From the perspective of a color blind person, some colors are impossible to distinguish. Sim Daltonism lets you visualize colors as they are perceived with various types of color blindness. Use the camera on your iOS device, or use the Mac app to filter a region of the screen.

Tenon.io

Tenon.io can identify 508 and WCAG 2.0 issues in any environment - even on your developer's laptop. Because production is a bad place to discover bugs.

Check your website for accessibility issues.

WebAIM: Color Contrast Checker

Ensure a proper contrast when choosing colors for your design.

StackBlitz

The online IDE for web applications. Powered by VS Code.

.0

CodePen

Front End Developer Playground & Code Editor in the Browser

WPO Stats

Case studies and experiments demonstrating the impact of web performance optimization (WPO) on user experience and business metrics.

If you have to tell your manager why you want to optimize the speed of your site.

Responsive Image Breakpoints Generator by Cloudinary

Easily generate the optimal responsive image dimensions. One image for all screen resolutions and different devices is not enough. An image per pixel is too much - so how can someone automatically choose the optimal responsive image sizes?

Sonarwhal, a linting tool for the web

Build better web sites - lint the web forward.

Dareboost

Website Speed Test and Quality Check

Charles Web Debugging Proxy

Charles is an HTTP proxy / HTTP monitor / Reverse Proxy that enables a developer to view all of the HTTP and SSL / HTTPS traffic between their machine and the Internet. This includes requests, responses and the HTTP headers (which contain the cookies and caching information).

Harry Roberts: Why Fast Matters

With more and more emerging markets coming online, and more and more apps moving to the web platform, we’re reaching an intersection where connections are getting slower and websites are getting heavier. In this talk, we’ll learn just what these emerging markets mean to us, and how we can begin to move in the right direction.

Accessibility Wins: Google Chrome’s Color Contrast Debugger

Chrome Canary’s developer tools have an experiment where you can debug color contrast right in the style inspector.

Request Map Generator

Submit a URL to generate a node map of all of the requests on the page. Rapidly identify what third-parties are on your site, where your transmitted bytes are coming from and how slow your domains are!

builder4impress - extremely WYSIWYG editor for impress.js

This tool allows WYSIWYG editing of impress.js presentations.

Alpha version, though. A bit rough around the edges.

Namechk: Username, Domain & Trademark Search

Use Namechk to see if your desired username or vanity url is still available at dozens of popular Social Networking and Social Bookmarking websites. Promote your brand consistently by registering a username that is still available on the majority of the most popular sites. Find the best username with Namechk.

Grav - A Modern Flat-File CMS

Yet another flat-file CMS option. In PHP, though.

Beeping

HTTP Monitoring via API - Measure the performance of you servers

Can I use... Support tables for HTML5, CSS3, etc

"Can I use" provides up-to-date browser support tables for support of front-end web technologies on desktop and mobile web browsers.

How to lose weight (in the browser)

And what if we got together a bunch of experts who work on large sites to create a definitive front-end performance guide?

And not just one of those boring guides made for robots, what if we did something fun?  That's exactly what we've done! And we'll guide you in this battle to create even faster sites.

Although I'm not a front-end dev this may come in handy sometime.