howdoi : Instant coding answers via the command line.
Babel : Babel will turn your ES6+ code into ES5 friendly code, so you can start using it right now without waiting for browser support.
Tabnine : Tabnine is an AI-powered code completion extension for IDEs
Browserling : Live interactive cross-browser testing
Insight.io brings IDE-like code intelligence features such as cross-reference, class hierarchy and semantic search, right into your browser and helps developers to work with more productivity.