Oleksandr Shepel

.NET 10 · PostgreSQL · RabbitMQ · Angular · Kubernetes

A multi-tenant backend where several independent games share one set of services — identity, economy, notifications — instead of each rebuilding auth, wallets and admin tooling. Built solo, infrastructure included.

• Microservices with database-per-service on PostgreSQL, behind an Ocelot API gateway.
• Transactional outbox over RabbitMQ — an event is never published unless the state change that caused it committed, and consumers deduplicate so a redelivery replays instead of double-granting.
• Auth built against a real threat model — refresh-token rotation with family-based reuse detection, audience-scoped RBAC, and a cookie flow that keeps tokens out of browser storage.
• Deployed, not demoed — Kubernetes and Argo CD GitOps on a VPS, with traces that follow a request across services and through the message broker.

Live demo ↗ Grafana ↗ Source ↗

Apr 2025 – present · sole developer in a 7-person team

Every technical decision across three mobile titles, plus sprint planning and estimation with the team. The main product is live, and I own its backend, its cost and its security.

• Backend business logic in C# Azure Functions over PlayFab — economy, inventory, crafting, clans, tournaments, chat, moderation, matchmaking and purchase validation.
• Brought infrastructure spend down to a few hundred dollars a month by cutting per-user request volume, caching client-side, rate limiting and restructuring how player data is stored.
• Designed a layered anti-cheat system in a week — device-level identity, Play Integrity and player reports combined into a trust score driving graduated automatic enforcement, inside Google and Apple platform policy.
• P2P multiplayer on Photon PUN 2, hardened with RPC validation and encryption on security-critical calls, since P2P gives the client authority by default.

May 2022 – Apr 2025 · small teams, high release cadence

A studio shipping at speed — 30+ titles to market test in a single quarter. I did feature work and became the person who built the tools everyone else worked in.

• Internal tooling — an asset importer that removed hours of manual texture setup, level tooling that cut construction from days to hours, and localisation wired to Google Drive so designers edited copy without a developer.
• Versioned save migration built into the save system itself, ending a recurring class of bug where updates broke players' saved data — and giving QA snapshots to test late-game states without replaying the game.
• Analytics, ad mediation and monetisation across the portfolio, wired to remote config so placement and frequency could be A/B tested live without a new build.
• Later moved off feature work to define a shared architecture standard — a modular base project with pluggable systems, so a developer joining an unfamiliar project found a structure they already knew.