Apr 2025 – Jun 2025 · Backend engineering

LANBuddies — Event & Tournament Platform

Mobile-first event and tournament app for organizations. Google OAuth, team assignments, live bracket visualization. Java / Spring Boot backend shipped to production.

Java
Spring Boot
MariaDB
Firebase Auth
Google Cloud Console
OAuth 2.0
Tomcat
Jenkins
Figma

Last updated June 30, 2025

Source: github.com/kimonsodu/LANBuddies

Context

Team of eight at Stockholm University, March–June 2025. Cross-functional Agile (Scrum) build covering the full lifecycle: user interviews, UX in Figma, implementation, testing, deployment. Tracked in ClickUp.

Product goal — let organizations run internal events and tournaments end-to-end on one app: browse events, register, get auto-assigned to teams, watch the bracket update as matches resolve.

Screens

LANBuddies start / welcome screen — Start — sign in with Google or continue as guest.

Events list — Events feed — search, sort, browse active tournaments.

Tournament bracket view — Tournament bracket — single-elimination layout, live winners.

My contribution

Backend + auth. Concretely:

Domain + API — core classes, Spring controllers, service layer. Unit and integration tests.
Auth — Google OAuth 2.0 via Firebase, wired on both backend (token verification) and frontend (sign-in flow).
Data — MariaDB schema, JPA mappings, migrations.
Ops — Tomcat deployment target, Jenkins CI/CD pipeline, staging → prod promotion.

Stack

Backend: Java, Spring Boot, MariaDB, Tomcat, Jenkins, OAuth 2.0. Auth + cloud: Firebase Authentication, Google Cloud Console (OAuth client + project config). Frontend + design: Figma, mobile UX/UI. Process: Scrum, ClickUp, cross-functional team of eight.

Takeaways

Shipped a full product from interviews to prod in ~3 months. Real lesson wasn't the tech — it was coordinating eight people across design, frontend, backend, and QA without any of the pieces drifting. OAuth on both sides of a mobile app is never as simple as the docs make it look.