GitHub: Build software better, together.

BitBucket: Git and Mercurial code management for teams

Visual Studio: Comprehensive collection of developer tools and services.

Swiftype: Add great search to any website. Free with limitations.

Coveralls: Test coverage history and statistics.

LingoHub: Free for Small Teams, Open Source usage and Educational projects.

Codacy: Continuous Static Analysis designed to complement your unit tests.

TinyCert: Free SSL certificates for your startup.

Pingdom: Website monitoring. Free for one website.

Rollbar: Full-stack error monitoring for all apps in any language.

Loggly: Simplify Log Management Forever. Free for one user.

Getting Real: The smarter way to build web apps. A free book by 37signals.

Peek: Get a free, 5-minute video of someone using your site.

Cody: A free library of HTML, CSS, JS nuggets.

Website Builders

HTML5 UP: Responsive HTML5 and CSS3 site templates.

Bootswatch: Free themes for Bootstrap.

Templated: A collection of 845 free CSS & HTML5 site templates.

WordPress.org: Create your new website for free.

Strikingly: Free, unlimited mobile optimized websites for strikingly domains.

Bootstrap Zero: The largest open-source, free Bootstrap template collection.