StatCounter - StatCounter is a simple but powerful real-time web analytics service that helps you track, analyse and understand your visitors so you can make good decisions to become more successful online.

Raygun - Raygun gives developers meaningful insights into problems affecting their applications. Discover issues - Understand the problem - Fix things faster.

Histats - Start tracking your visitors in 1 minute!

Kafka - Apache Kafka is publish-subscribe messaging rethought as a distributed commit log.

Matomo - Matomo is an open-source web analytics platform

Sentry.io - From error tracking to performance monitoring, developers can see what actually matters, solve quicker, and learn continuously about their applications - from the frontend to the backend.