1. Dash is an API Documentation Browser and Code Snippet Manager. Dash searches offline documentation of 200+ APIs and stores snippets of code. You can also generate your own documentation sets.

  2. Documentation and Test Consoles for Over 150 Public APIs

  3. Open source API documentation browser with instant fuzzy search, offline mode, keyboard shortcuts, and more

  4. Compatibility tables for support of HTML5, CSS3, SVG and more in desktop and mobile browsers.

  5. "Can I use" for email. Quickly view if a tech is supported by all email clients.