Arsen

ARSEN ROMANENKO
FULL STACK DEVELOPER
[open contact info](look above in the "contact info" section) [open contact info](look above in the "contact info" section) Lviv, Ukraine | Remote/Relocation

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Full-stack developer with 3+ years of experience building and shipping production SaaS on
TypeScript, Next.js / React and Node.js. I own features end to end: data model and API contract,
business logic, UI and release. Experienced with payment and subscription integrations,
ClickHouse-backed product analytics, async job pipelines, i18n at scale and server-side A/B
testing. BSc in Cybersecurity, English B2, comfortable in async distributed teams.

PROFESSIONAL EXPERIENCE
Ruby Labs – Full-stack Software Developer
Jul 2025 – Present | Remote
Build and own GetQR, a dynamic QR-code SaaS, on Next.js 15 / React 19 / TypeScript,
delivering features end to end across backend, frontend, database and infrastructure.
Design REST APIs and server actions with Zod validation, RBAC, rate limiting and OpenAPI
generation; work with Prisma / PlanetScale MySQL and enforce data integrity at the application
layer.
Integrated the payment and subscription stack (PayNext, Primer, Stripe, PayPal), implementing
trials, dunning, refunds, webhooks, anti-fraud and geo-dependent pricing/paywalls.
Built analytics and experimentation infrastructure using Tinybird / ClickHouse, Recharts,
GrowthBook and server-side A/B testing to measure product, pricing and funnel performance.
Implemented async processing and server-side QR generation pipelines using Vercel Cron,
Upstash QStash, Redis locks, Sharp, Canvas and OpenType, including bulk generation, custom
fonts, ZIP exports and scheduled PDF reports.
Scaled the platform to 32 locales with next-intl, including RTL, localized routing and SEO; also
built an internal job-application platform from 0 to 1 with LLM-based resume parsing, vacancy
aggregation, deduplication, search, matching and dashboards.

PROFESSIONAL EXPERIENCE (CONT.)
FiveM (CFX.re) Server - Full-stack Developer
Jun 2024 - Feb 2025 | Remote
Built and maintained full-stack web tooling (React, Redux, TypeScript, Node.js, Nest.js) for a multiplayer
server with a large, active player base.
Designed REST APIs and real-time features against a live production server, where a bad release meant
downtime for hundreds of concurrent players rather than a broken pixel.
Read and debugged unfamiliar codebases fast under production load; owned testing, release
management and rollbacks via Git.
Freelance / Self-employed - Full-stack Developer
Jan 2023 - Jun 2024 | Remote
Delivered end-to-end websites and web applications for multiple clients, from requirements gathering to
launch (TypeScript / JavaScript, React, Node.js).
Integrated third-party services (payments, CMS, analytics, email) and handed over documented,
maintainable codebases.
Applied responsive design, accessibility and performance best practices across desktop and mobile.

SKILLS

Languages: TypeScript, JavaScript (ES6+), SQL, HTML5, CSS3
Frontend: React 19, Next.js 15 (App Router), Redux, Material UI, Sass (SCSS), BEM, Recharts,
responsive and accessible UI
Backend: Node.js, server actions, REST API, Zod, Nest.js, Express, OpenAPI, RBAC, rate limiting,
WebSockets
Data: Prisma, MySQL / PlanetScale, MongoDB, Redis (Upstash), ClickHouse / Tinybird
Payments and growth: Stripe, PayPal, Primer, PayNext, GrowthBook (A/B testing), Customer.io,
Mixpanel, GTM
Infrastructure and tooling: Vercel, Turborepo, pnpm, Vercel Cron, Upstash QStash, Git / GitHub,
Webpack, Sentry, Better Stack
Other: next-intl (i18n, RTL, 32 locales), SEO (hreflang, canonical, programmatic pages), sharp,
@napi-rs/canvas, Figma
English: B2 (Upper-Intermediate)

EDUCATION
Lviv Polytechnic National University - Bachelor’s degree in Cybersecurity | 2021 - 2025 | Lviv,
Ukraine
Information security, network security and cryptography - a background I apply to auth, RBAC and
payment-flow security.

Additional education: Full-stack course at Mate academy; Udemy - JavaScript Essentials,
Responsive Web & Mobile Development (HTML, CSS, JavaScript); MDN and React.dev self-study;
CodeWars.