Олексій

OLEKSII SHAPOVALOV
[відкрити контакти](див. вище в блоці «контактна інформація») | github.com/Mistesq | LinkedIn
Full-Stack Developer (React / Node.js) · Ukraine (Remote)

Summary
Full-stack TypeScript developer building for the web commercially since 2020, six years at one company from Junior
to Senior, most of it in production e-commerce. I primarily focused on React frontends and the server layers behind
them: BFF architecture, Shopify app backends (Node.js, Prisma/PostgreSQL), and third-party integration services.
On my last commercial project I owned the technical side of a ~97k LOC headless storefront, working directly with
the client’s PM: architecture, release process and performance, with p75 LCP taken to the origin’s best on record
and held flat through Q4 peak season. I build with a spec-driven AI-assisted workflow (Claude Code: specs, custom
review subagents, skills); the full process is open in my flagship project below.

At a glance: ~97k LOC headless storefront and a ~49k LOC B2B platform, top or co-top contributor on both · p75
LCP 6.1s → 2.2-2.5s (CrUX field data) · flagship project: live demo, 39 specs, 490+ tests

FLAGSHIP PROJECT
CodeVault: AI-powered code snippet manager | Live | GitHub
• Architected the app around Next.js Server Components and Server Actions with strict layer separation enforced
by checked-in standards and agent audits: components render, reads in a server-only data layer, mutations in
Zod-validated server actions
• Developed entirely through a spec-driven agentic workflow: 39 archived feature specs and 4 custom Claude Code
review subagents (auth-auditor, code-scanner, ui-reviewer, refactor-scanner); full paper trail in the repo
• Built the auth and security surface: NextAuth v5 (credentials + GitHub OAuth), email verification and password
reset with hashed single-use tokens, ownership-scoped queries, Upstash Redis rate limiting, and demo-account
protection (server-side operation guards, throttled reset-on-login)
• Implemented Stripe billing: Free/Pro plans via hosted Checkout and Customer Portal, webhook-driven
subscription sync, and server-side plan gating
• Shipped AI features on a two-tier Gemini strategy (flash-lite for tagging and summaries, flash for explanation
and optimization) and integrated external services with graceful degradation, each optional at boot: Cloudflare
R2 uploads, Upstash Redis, Resend email
• 490+ unit tests (Vitest) across 46 files with fully mocked collaborators, CI pipeline (lint → test → build)
Stack: Next.js (App Router), TypeScript, Prisma, PostgreSQL (Neon), NextAuth v5, Stripe, Gemini API, Cloudflare
R2, Upstash Redis, Vitest, GitHub Actions

EXPERIENCE
Independent Developer (Full-Stack) 01/2026 - Present
Remote
Built and shipped CodeVault end-to-end (flagship project above); paid part-time contract work on production
Node.js/Express codebases (internal tools; MongoDB, PostgreSQL): API endpoints and bug fixes. Alongside client
work, deepened the backend and infrastructure side: built a NestJS service (TypeORM, PostgreSQL, guards and
DTO validation) and deployed it on AWS with CDK as infrastructure-as-code (ECS Fargate behind an ALB, RDS in
isolated subnets, Secrets Manager, migrations as a separate one-off task).
Senior Frontend Developer → Full-Stack Developer 10/2024 - 01/2026
GoInteger Remote
Karma and Luck (long-term client): headless Shopify storefront (karmaandluck.com) · 01/2025 – 12/2025
Hydrogen / React Router 7 on Oxygen workers, ~97k LOC; rejoined the client whose Hydrogen v1→v2 migration

I led in 2023 (see below); the project’s primary developer, working directly with the client’s PM and owning the
technical side end-to-end
• Owned key technical decisions: platform migration strategy, server/BFF architecture, CSP policy, and release
management
• Proposed and drove the switch to a versioned release-train workflow (release/3.x, scheduled releases with
mid-week micro-releases scoped by change type); authored the release process documentation
• Set up a dedicated dev Weaverse store as a staging environment and reworked the team’s feature-delivery and
QA process around it
• Led the Remix v2 → React Router 7 migration (125 files) bundled with React 18→19 and Weaverse v4→v5, the
largest technical change in the repo that year
• Engineered a server-side gift-with-purchase engine hooked into all Shopify cart mutation paths: tiered gifts from
post-discount totals via line attributes, gift-only PDPs gated with 404s
• Maintained the BFF layer: 15 API resource routes, server-side analytics (own PixelBridge for first-party pixel
events), nonce-based strict-dynamic CSP across ~15 third-party scripts (Klaviyo, Yotpo Loyalty, Rep AI, GTM/
Elevar, Okendo, Postscript…)
• Built 30+ CMS-editable Weaverse sections incl. a multi-step bundle-builder (filterable grid, variant options, tiered
discounts; 5k+ LOC initial implementation)
• Owned storefront performance: drove all Core Web Vitals optimization work (LCP fetchpriority hints, CLS
elimination, preload strategy, third-party deferral) and mentored the team on performance-safe patterns; p75 LCP
recovered from a 6.1s post-launch peak to a stable 2.2–2.5s, the origin’s best on record, held flat through Q4 peak
season (CrUX field data)
• Onboarded and mentored the second core developer (part-time ramp-up to full velocity within ~3 months)
Custom Shopify apps (Remix, Node.js, Prisma + PostgreSQL) Built and maintained several custom apps for
client stores; the largest is a print-on-demand product configurator integration:
• Built a server-side API layer (7 endpoints) bridging the storefront with the Printformer API: draft configuration
lifecycle, guest-to-customer identity merge, Bearer-auth proxying with credentials stored server-side
• Automated product variant lifecycle via Shopify Admin GraphQL API: dynamic variant creation per customer
configuration and scheduled bulk cleanup with last-variant protection
• Implemented OAuth flow, app webhooks, and session persistence (Prisma/PostgreSQL); shipped a theme app
extension (PDP block) and an embedded admin settings page; deployed via Docker to Heroku with Bitbucket
Pipelines CI
Middle Frontend Developer 01/2022 - 10/2024
GoInteger Remote
Karma and Luck: Hydrogen v1 → v2 (Remix) migration · 08/2023 – 01/2024
• Migrated a production storefront burdened with heavy tech debt from Hydrogen v1 to Hydrogen v2 (Remix),
resolving long-standing developer-experience issues and improving lab performance scores; the client later
re-engaged me to lead their next platform migration (2025)
• Built a custom product page with a dynamic product-customization builder
Wondertrunk (outstaff placement at Westlink): B2B travel-operations platform · 03/2024 – 11/2024
React 18, TypeScript (strict), MUI, TanStack Query; ~49k LOC, 26 routes; top contributor over my 7 active months
on the project: ~39% of all commits, 2x ahead of the next contributor
• Owned the trip pricing engine’s business logic: aggregate trip totals, net/gross/markup/margin/commission math,
multi-currency support, and a lock/unlock recalculation engine (~1,600 LOC): lock any pricing field, the rest
recompute around it
• Led the core itinerary builder: day-by-day AM/PM scheduling, per-service price options, outline configuration,
version history with restore, and a quote-export drawer (119/190 commits on the central orchestrator)
• Rebuilt the supplier catalog (v2): editable pricing grid with 7 inline-edit cell components (~1,700 LOC), media
upload flow, Google Maps/Places integration
• Designed a generic typed CRUD API factory (createCrudAPI<T>) with pagination, sorting, and filter serialization,
the foundation for all 22 domain API modules

• Built HTML itinerary export: programmatically generated, outline-filtered schedule tables copied to the clipboard
for client-facing documents
• Drove two structural refactors (import/schema normalization; Trip-page architecture) and managed release-train
merges across develop/staging/production
Client portals (React + TypeScript, Westlink placement) · 2023–2024
• SwapItFast: seller/buyer marketplace portal with Stripe subscription billing (Checkout + Customer Portal), TalkJS
chat, Google Analytics, MUI
• Lucky: client order portal with Stripe SetupIntents for secure payment-method storage, admin panel for client
management
• MySoulVibe2 (Thea): sound-recording portal with admin panel, analytics dashboards (Google Charts, Recharts)
Demo videos available on request.
Junior Frontend Developer 02/2020 - 01/2022
GoInteger Remote
• Developed and maintained custom Shopify themes (Liquid, JavaScript/jQuery) for client stores; integrated
third-party Shopify apps (Algolia, Accentuate, Recharge)
• Improved page load speed by ~20% across client storefronts through script optimization and deferred third-party
loading (measured via Lighthouse, Shopify performance reports, and Search Console CWV)
• Migrated legacy themes to Shopify Online Store 2.0; transitioned to React-based projects

SKILLS
Core: TypeScript, JavaScript, React, Next.js
Backend & Data: Node.js (Express, NestJS, Remix/React Router server runtime), SQL, PostgreSQL, Prisma,
TypeORM, MongoDB, REST APIs, BFF architecture, GraphQL
Cloud & Infrastructure: AWS (ECS Fargate, RDS, CDK, Secrets Manager, ALB), Docker, GitHub Actions CI
AI-assisted & spec-driven development: Claude Code (custom subagents, skills, MCP: Neon, Playwright,
Context7), spec-driven workflow, GitHub Spec Kit, Gemini API integration
E-commerce: Shopify (Hydrogen, headless storefronts, custom apps, Oxygen), Stripe
Performance: Core Web Vitals optimization, Lighthouse/PageSpeed, Search Console, script loading strategies
Testing: Vitest, React Testing Library, Playwright
Styling & UI: Tailwind CSS, shadcn/ui, Radix UI
Tooling: Vite, Biome/ESLint, GraphQL Codegen

EDUCATION
Master's programme (incomplete), Computer Science 2018 - 2019
Donbas State Mechanical Engineering Academy Ukraine
Bachelor's degree, Computer Science 2016 - 2018
Donbas State Mechanical Engineering Academy Ukraine

LANGUAGES
Ukrainian: native · Russian: native · English: Upper-Intermediate (B2)