Case study 02 / Skill Up
A skill-tournament platform, built solo
Skill Up is a skill-based esports app where players pay to enter tournaments and win prizes. I was the only engineer on it: iOS, Android and the back end.
Result
Sole full-stack engineer
2025 – 2026
React Native, Skia, Node.js, PostgreSQL, Stripe
Mobile, back end, payments, anti-cheat
The problem
When money rides on a score, every part of the product becomes a trust problem. The game had to feel instant on a phone, two players entering the same tournament had to get exactly the same puzzle, and a score arriving from a client could never be taken at face value. All of it built by one person, for iOS and Android.
Architecture
- I built
- Managed service
- Trust boundary
- 01Matches a build point
What I built
A custom real-time game engine: an 8×8 block-placement game in React Native with Skia and Reanimated, holding 60 FPS with combo scoring and timed mechanics.
Server-authoritative anti-cheat: the server recomputes every score from batched client moves, checking sequence integrity, timestamp monotonicity and sanity caps.
A shared seeded RNG that deterministically generates identical piece sequences on client and server, so every entrant plays the same board.
Payments through Stripe and Apple In-App Purchase with server-side receipt verification, behind one pluggable provider abstraction with idempotency keys.
A concurrency-safe tournament and ticketing system in PostgreSQL with transactional guards on ticket capacity, entry caps and wallet limits, plus XP and levelling, a timezone-aware daily reward wheel, biometric login, age-gated onboarding and EN/FR localisation.