The architecture is a static asset server (nginx), basic backend app server (node js), routing engine (Java) which is a fork of graphhopper, fast geocoder named photon (elasticsearch), full OSM places search called Nominatim that feeds photon (postgres) as well as a few asynchronous jobs that pull the latest OSM and transit data then rebuild the search indexes.

This was on a k8s cluster for a bunch of reasons. We eventually scrapped it and put the stack in one box instead of five.