Skip to content
← Portfolio

Yaroslav Tsarenko

Backend-leaning full-stack engineer · Node.js, TypeScript, PostgreSQL, React

  • dev@yaroslavtsarenko.com
  • t.me/yyrrsllvv
  • linkedin.com/in/yaroslav-tsarenko-/
  • www.yaroslavtsarenko.com
  • Ukraine · UTC+2 / +3

Since 2021 I've shipped Node.js, TypeScript and React to production: order pipelines and background workers for a US platform, multi-provider payments for EU storefronts, OpenAI features inside logistics tooling, and offline-first software for Ukrainian defense-tech. Open to remote Middle+ roles and B2B contracts.

Experience

  1. Software Engineer · ArmySOS

    06/2026 — now

    Defense-tech · product details under NDA · Ukraine · Remote

    • Field software for Ukraine's defense sector, built for low-connectivity environments.
    • Offline-first flows, resilient sync and background services; REST and push integrations.

  2. Full-Stack Engineer, contract · Independent

    2023 — now

    EU e-commerce studio, Latvia — long-term client · Latvia · Remote

    • Internal payment layer across Stripe, PayPal and high-risk PSPs: routing, idempotent webhooks, daily reconciliation.
    • Storefronts for eSIMs, digital goods and PDF-generation tools — from schema to deploy.

  3. Back-End Developer · SimplyDepo

    11/2025 — 04/2026

    US e-commerce & order management · United States · Remote

    • Moved notification dispatch behind a job queue with retries and dead-letter handling — user-facing endpoints stopped waiting on it.
    • Rewrote large-report PDF generation as streaming background jobs, removing a class of admin-side timeouts.
    • Profiled the slowest endpoints; targeted indexes and N+1 rewrites brought P95 down on order lists.

  4. Front-End Developer · Tresor.tech

    09/2024 — 02/2025

    Ukraine · Remote

    • Shipped 20+ cross-browser production interfaces in React, TypeScript and SCSS (BEM).
    • Booking forms backed by Node.js and MongoDB; code-splitting and image work cut load time by ~30%.

  5. Full-Stack Developer · Allship.ai

    08/2023 — 08/2024

    US logistics platform · United States · Remote

    • Shipped three AI-powered logistics features; OpenAI answers 20+ operator questions against the domain database.
    • Kanban ticketing for dispatch teams; Jest coverage on core flows to 85%, production crashes down ~20%.

  6. Front-End Developer · StreamGenix

    05/2021 — 07/2023

    Ukraine · Remote

    • Built a CRM with the backend team that lifted customer retention ~20%.
    • Frontend test automation to 88% coverage; GitLab CI across 9 web properties.

Skills

Backend
Node.js, TypeScript, Express, REST, WebSockets, Job queues, Webhooks, PDF pipelines
Data
PostgreSQL, Prisma, Supabase, MongoDB, Redis
Frontend
React, Next.js App Router, Tailwind CSS, SCSS, Redux Toolkit, Zustand, WebGL
Payments
Stripe, PayPal, Spoynt, Transfermit, SmartCore
AI
OpenAI API, Structured outputs, RAG, Claude Code
Infra & quality
Docker, GitHub Actions, AWS, Vercel, Jest, Playwright

Selected projects

  • AllShip AI marketplaceThree legacy codebases became one marketplace with escrow, four roles and an AI assistant. www.yaroslavtsarenko.com/work/allship-ai
  • Order platform backendTurned slow synchronous work into predictable background jobs. www.yaroslavtsarenko.com/work/order-platform-backend
  • Multi-PSP payment layerProvider-agnostic charges, refunds and webhooks with daily reconciliation. www.yaroslavtsarenko.com/work/payment-orchestration
  • AI logistics featuresOpenAI answers over live shipment data; real-time tracking; tested dispatch flows. www.yaroslavtsarenko.com/work/ai-logistics
  • eSIM storefrontOrders as a state machine with automatic compensation on provider failure. www.yaroslavtsarenko.com/work/esim-store
  • Skins marketplaceSold-elsewhere items disappear before anyone pays for them. www.yaroslavtsarenko.com/work/skins-marketplace
  • Lodge booking engineThe database itself makes a double booking impossible. www.yaroslavtsarenko.com/work/lodge-booking
  • Game keys storeInstant key delivery for honest buyers, a manual hold for risky orders. www.yaroslavtsarenko.com/work/game-keys-store

Education

  • BSc, Computer Science

    Khmelnytskyi National University · 2022 — 2026 · Grade 94 / 100

  • Web Development with HTML, CSS, JavaScript

    IBM · certificate · 2024 · Credential IW0YYY47OD27

Languages

  • English — B2, daily with US & EU teams
  • Ukrainian — Native
  • Polish — Conversational