The full story · Oct 2026 to now · the mobile app and admin are Gowrish's; the backend is mine

UniNeeds

The backend behind a live college app, built so the app never noticed.

7services behind one gateway

1,373tests, 826 of them on real Postgres and Kafka

0changes needed in the app

0production incidents since it went live

The hard parts

Matching what the app silently relied on

Problem: The app was already in students' hands, could not change, and also reads the database directly.
What I did: I listed the traps first: Firestore number types, which handler Express really runs, how JavaScript prints numbers and dates. Tests compare the stored documents byte for byte, not just the responses.

One order's events, in order

Problem: Two copies of the event relay could send updates for the same order out of order.
What I did: The database hands events out strictly in sequence for each order, while different orders still flow in parallel. Consumers ignore repeats.

Also in it

The app covers food ordering, ride pools, rentals, gadget repairs, a campus store and chat
A gateway plus identity, payment, store, food, rental, chat and notification services
Each service owns its own Postgres schema and database role
Events through a transactional outbox on Kafka, with read models instead of cross-service queries
Firebase, Razorpay and email integrations
Packaged with Docker and Helm, monitored with Prometheus and Grafana

Built with

GitAutomated testingJavaRESTDockerSQLSpring BootMicroservicesDocker ComposeRedisBashTransactional outboxPostgreSQLKafkaJUnitTestcontainersGrafanaSpring Cloud GatewayJPA / HibernateHelmFlywayContract testingWireMockPrometheus

See the app on Google Play All projects