Aliaksei K.

Front-end Developer

Upwork • Freelance

Dec 2025 - May 2026 • 5 mos

Frontend Developer — AI video-generation platform, 200+ active users/hour. Role: owned the caching modules and shipped features autonomously inside an existing product team’s codebase. • Delivered new features end-to-end in a live Next.js + TypeScript codebase with minimal onboarding, coordinating async with a remote product team. • Diagnosed and fixed video/image caching bugs that caused production rendering failures across async pipelines — resolved recurring render errors affecting live users. • Integrated third-party AI APIs and async video-processing workflows with reliable job queuing and retry handling.

Full-Stack Developer

AmRest • Full time

Sep 2024 - Oct 2025 • 1 yr 1 mo

Full-Stack Developer (Remote) — Internal delivery-ops SPA for AmRest on Azure: 500–600 couriers, up to 9,000 orders/day across Poland. Role: frontend owner of the live tracking and dispatch dashboards, integrating with backend teams. • Built per-restaurant order tracking and courier dashboards (React, TypeScript, Mapbox) used daily by dispatch operators to manage the full order lifecycle. • Implemented real-time courier tracking in a microfrontend architecture on Azure — streamed geolocation synced against live order state, handling concurrent updates without stale UI at 9k orders/day scale. • Integrated order-sync and dispatching APIs; reconciled concurrent updates so operators always saw a correct, current picture during peak load.

Full-stack Developer

CoinTrade • Full time

Aug 2023 - Aug 2024 • 1 yr

Full-Stack Developer (Remote) — B2B/B2C crypto payment platform: 20+ coins, invoicing, multi-wallet accounting. Role: fully owned the frontend application — built everything from scratch through to production. • Built the entire merchant-facing frontend from scratch to production (React, TypeScript): invoicing, multi-wallet accounting, analytics dashboards, and business/admin modules. • Implemented live payment-status updates over WebSockets — the tricky part was keeping wallet balances and invoice state consistent as confirmations arrived out of order across 20+ chains. • Rebuilt a high-drop-off multi-step payment flow: profiled where users abandoned, reworked the UX and validation, cutting payment failures by [50%]. • Developed the Node.js API layer for payment endpoints with error handling and retry logic to stay reliable against flaky provider responses.