Glympse - Glympse is the easy way to safely share your location in realtime. No sign-up needed.
GeoSpark - Location tracking SDK with 90% less battery drain 🔋
Zenly - Zenly is a GPS tracker to locate your friends in realtime.
Iris - The fastest web framework for Go in (THIS) earth
OwnTracks - Cross-platform location sharing
Citizen - Stay safe with instant alerts about nearby crime