diff --git a/.env.example b/.env.example
index 7c93a85..3ed7ead 100644
--- a/.env.example
+++ b/.env.example
@@ -1,9 +1,10 @@
 # ---- Database (external Postgres) ----
-# When running the app via docker-compose, host is the compose service name
-# "postgres" on the internal port 5432 (NOT the published host port).
+# With docker-compose the app reaches Postgres via the UNIQUE container name
+# "pleinr-postgres" on the internal port 5432 (avoids collisions with other
+# "postgres" containers on a shared proxy network; NOT the published host port).
 # For local dev outside Docker against the dockerised Postgres, use
 # localhost on the published host port: postgres://pleinr:pleinr@localhost:54329/pleinr
-DATABASE_URL=postgres://pleinr:pleinr@postgres:5432/pleinr
+DATABASE_URL=postgres://pleinr:pleinr@pleinr-postgres:5432/pleinr
 
 # Individual vars consumed by the postgres container in docker-compose.yml
 POSTGRES_USER=pleinr
diff --git a/docker-compose.yml b/docker-compose.yml
index ca87cc1..40d7434 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -34,7 +34,10 @@ services:
       postgres:
         condition: service_healthy
     environment:
-      DATABASE_URL: postgres://${POSTGRES_USER:-pleinr}:${POSTGRES_PASSWORD:-pleinr}@postgres:5432/${POSTGRES_DB:-pleinr}
+      # Use the UNIQUE container name (not the generic "postgres" alias) to avoid
+      # name collisions with other "postgres" containers on the shared proxy
+      # network. pleinr-postgres only exists on our internal network.
+      DATABASE_URL: postgres://${POSTGRES_USER:-pleinr}:${POSTGRES_PASSWORD:-pleinr}@pleinr-postgres:5432/${POSTGRES_DB:-pleinr}
       # Optional: if left empty, the container generates and persists one
       # automatically (see docker-entrypoint.sh + the app-data volume).
       AUTH_SECRET: ${AUTH_SECRET:-}