case study · P/01

oneKampus

Institutes juggle separate tools for admissions, fees, classes, exams and hiring, and none of them talk to each other. oneKampus puts all four in one product, with one login across a web app and a mobile app.

Role: Founder · sole engineer
Timeline: Oct 2026 — present · 219 commits
Platforms: Web · iOS · Android
Links: Private — demo on request

What I built, layer by layer.

backend

Spring Boot modular monolith

Four modules — IMS, LMS, Exams, Hiring — each with its own Postgres schema, connection pool and Flyway history
Single sign-on: one JWT carries institute and LMS claims, valid across every module
Stripe checkout with signed webhooks; S3 storage via AWS SDK v2
Exam engine with auto + manual grading, ranks and percentiles
Modulith boundary tests keep modules from leaking into each other

Java 17 · Spring Boot 4.1 · Modulith 2.0 · Security · JPA · Flyway · springdoc

frontend

Next.js web app

65 pages: admin, teacher, student and parent portals
Full-screen proctored exam player
Live video interviews over WebRTC, plus recorded-answer interviews with MediaRecorder
HLS video lessons with hls.js

Next.js 16 · React 19 · MUI 7 · Redux Toolkit · TanStack Query

mobile

React Native app

31 screens sharing the same API and login
Video lessons, attendance, fees and results on the phone
Server state cached with TanStack Query

React Native 0.88 · React Navigation 7 · react-native-video

infra

CI and deployment

GitHub Actions runs 34 test classes on embedded Postgres, builds Docker images, ships over SSH
JVM tuned for a 1 GB box (256 MB heap, C1 JIT) — measured ~410 MB under load
Caddy behind Cloudflare with origin certificates and real-IP rate limiting

Docker Compose · Caddy · Cloudflare · AWS Lightsail · GitHub Actions

Engineering decisions.

01A modular monolith, not microservicesOne deploy and in-process calls keep a solo-run product cheap and debuggable. Boundaries are enforced by Modulith tests instead of the network, so any module can be extracted later.
02A Postgres schema per moduleEach module owns its tables and migrations, which isolates change and makes extraction possible. The cost: no cross-schema foreign keys and four connection pools on a small server.
03WebRTC signalling over HTTP pollingPolling every second through the existing API avoided running a WebSocket server behind Cloudflare and Caddy. It trades a little latency and request load for much simpler infrastructure.

By the numbers.

counted from the repository

387REST endpoints

108JPA entities

65 + 31web pages + mobile screens

4product modules

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