Node.js - Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications
Slack - A messaging app for teams who see through the Earth!
Ruby on Rails - Ruby on Rails is an open source full-stack web application framework for the Ruby programming...
Mattermost - Mattermost is an open source alternative to Slack.
Django - The Web framework for perfectionists with deadlines
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.