Private networking between services
4 min readUpdated August 2026
Apps and add-ons in the same phase share a private network. You do not open a tunnel or paste public database URLs. Attach the add-on and use the injected host or URL.
Step by step
01
Keep workloads on the same phase
Private reachability is per phase (environment). An app in staging does not automatically see production add-ons.
02
Attach add-ons instead of public URLs
Wire Postgres or Valkey on the canvas. Use DATABASE_URL / PG* or REDIS_URL from Variables after attach. Do not expose the database on the public internet.
03
Call sibling apps by their in-phase name
Another app on the same phase is reachable on the private network without a custom domain. Prefer injected URLs over hand-built hostnames.
No private-DNS settings page
There is no Networking → Private DNS panel. If two apps cannot talk, check they are on the same phase and that the add-on is attached.