Semyon A

Tail Trails (pet project)

Self Employed • Indépendant

Jun 2026 - Present • 3 mos

PS1-style 3D racing sim where cats compete. Built entirely through agentic coding in Claude Code — no hand-written code; my role was architecture, task breakdown, and review. - Split a deterministic, engine-free game core (unit-tested) from the Godot scene layer, so core logic runs in CI independent of rendering. - LAN multiplayer with split authority: client-owned movement (zero input lag), server-authoritative race state (laps, positions, finish). - Scenes built in code, not hand-edited .tscn trees — no drift, no unreadable diffs. - Ran the whole build as an AI-driven pipeline (Claude Code + Superpowers plugin): every change goes through brainstorming, planning, TDD, and code review before merge. - Procedural low-poly meshes and a custom PS1 shader, zero external 3D assets. About the project — https://github.com/Qialet/tail-trails

FullStack developer

Unity • Temps partiel

Aug 2025 - Present • 1 yr 1 mo

Loyalty platform for hospitality venues: cafes, computer clubs, hookah bars. (UNITY SYSTEMS LTD) - Built Stripe Subscriptions integration end-to-end: webhook-driven plan lifecycle, local mirror of the Stripe product catalog, three paid tiers plus free trial, proration-aware upgrade/downgrade, and add-on locations scoped to the top-tier plan. - Designed a unified transactional endpoint handling bonus accrual, redemption, and cashback across three loyalty subsystems (staff, customers, cashback) — APNs push notifications are coupled to the same pipeline. - Delivered Apple Wallet integration: server-side .pkpass generation, APNs pipeline configuration, transaction-triggered and owner-initiated promotional push updates, certificate lifecycle management. - Shipped the customer portal in React from Figma mockup to production; built a parallel staff-facing interface with Square POS integration. - Contributed UX/UI decisions throughout the product build phase, going beyond the engineering scope to improve product quality and user flows.

Backend developer

Company • Temps plein

Jan 2025 - Aug 2025 • 7 mos

Driver-side platform for personal vehicle ride-hailing. (Rulyou.ru) - Architected Keycloak from scratch in Docker: realm, clients, role mapping. Configuration is stored in the repository and deployed to production via automated import — zero manual steps. Built a NestJS abstraction layer (registration, login, session management, IP allowlist, token handling) that fully decouples the rest of the system from Keycloak internals. - Optimized a legacy MySQL database with no indexes or foreign keys: rewrote sequential queries as JOINs, applied targeted indexing, moved residual filtering to the application layer. Response time: 800 ms → 150 ms (−81%). - Eliminated N+1 patterns in batch statistics aggregation using raw SQL via Kysely — rewrote query logic to process data in a single pass. Execution time: 60 min → 10 min (−83%). - Designed and implemented a driver cashback system with an automated business metrics collection pipeline.