Open source alternative to Segment - GitHub

Privacy and Security focused Segment-alternative, in Golang and React - rudderlabs/rudder-server

Rudder is an open-source Segment alternative written in Go, built for the enterprise. https://rudderlabs.com.

Long answer: Rudder is a platform for collecting, storing and routing customer event data to dozens of tools. Rudder is open-source, can run in your cloud environment (AWS, GCP, Azure or even your data-centre) and provides a powerful transformation framework to process your event data on the fly.