A combination of PostgreSQL + PostGIS + pgRouting, Java + GraphHopper and my personal favorite: PostgREST!

Hey haolez, glad to hear you like PostgREST :)(I'm the current maintainer).

If you manage to open source your project please stop by our docs repo, would be great to have a real world PostGIS project in our ecosystem list.

Will do! Congratulations, btw. PostgREST is incredibly stable :)

Sounds like the folks at https://osgeo.org might be interested...