Zabbix - Track, record, alert and visualize performance and availability of IT resources
Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Memrise - Learn a new language with games, humorous chatbots and over 30,000 native speaker videos.
Prometheus - An open-source systems monitoring and alerting toolkit.
Busuu - Join the global language learning community, take language courses to practice reading, writing, listening and speaking and learn a new language. Learn English with busuu's .