Web · Mobile · AI

Ideas in.Productsout.

Eight years turning ambitious specs into web apps, mobile apps and Chrome extensions that 10,000+ people use daily. Angular, React, React Native – from system architecture to the last easing curve.

Portugal / Ukraine – available for new projectsscroll

Capabilities

full cycle – idea to store

Web platforms

Enterprise Angular & React systems that stay fast past 100k lines – dashboards, marketplaces, fintech backends for the frontend.

Angular · React · Next.js

Mobile apps

React Native for iOS & Android – one codebase, genuinely native feel, shipped to both stores and used by real teams every day.

React Native · iOS · Android

AI extensions

Chrome extensions with AI under the hood – from architecture and store review to 10,000+ active users on Upwex alone.

Chrome · Manifest V3 · AI APIs

Tech leadership

The CTO playbook: system design, legacy rescue, code-review culture and mentoring for teams that want to move faster.

CTO · Audits · Mentoring

Services

what you can hire me for

~/services/web-app-development

$

  • Production-ready application
  • Architecture that scales
  • Test coverage that matters
  • Legacy migration
Angular · React · Next.jsOpen service ↗

Selected work

2017 → 2026

Not case studies live products with real users behind every pixel.

Upwex – interface screenshot
01 ⁄ 04

Upwex

AI copilot for Upwork freelancers – proposal generation, lead scoring, CRM sync. Built from zero as CTO & co-founder.

CTO · Co-founderReact · AI · Chrome Extension
Visit site
Sharebite – interface screenshot
02 ⁄ 04

Sharebite

The meal-benefits platform feeding NYC's biggest teams. Frontend across the web platform and the React Native app.

Frontend EngineerAngular · React Native
Visit site
Aerapass – interface screenshot
03 ⁄ 04

Aerapass

Fintech infrastructure – payments, KYC flows and operator dashboards for a global payment ecosystem.

Frontend EngineerAngular · Fintech
Visit site
SunCrypters – interface screenshot
04 ⁄ 04

SunCrypters

Web3 studio site with heavy motion design – built to prove a point about what the browser can do.

Frontend DeveloperReact · Next.js · Web3
Visit site

Track record

2017 → today

0+
years shipping – from pixels to production
0k+
daily users on products I architected
0+
critical bugs hunted down and killed
0
platforms mastered: web · mobile · extensions

About me

the human behind the commits

I'm Serhii – an engineer who treats your product like a co-founder would.

Eight years ago I wrote my first production Angular app; today I run engineering at Upwex, the AI copilot I co-founded for Upwork freelancers. In between: rescuing legacy codebases at scale, leading frontend teams, and shipping web and mobile products that 10,000+ people use every day.

My lane is the full frontend lifecycle – architecture, build, tests, performance, store review – plus enough Node.js (NestJS, MongoDB) to design the API I'm consuming. I care about the boring things that make products fast: typed contracts, measured performance and code the next engineer can read without me in the room.

  • Base Portugal / Ukraine
  • Roles CTO · Frontend Engineer
  • Since 2017 – shipping for real users
  • Education M.Sc. Engineering, ZNTU

Writing

notes from the trenches

FAQ

before you write

Yes – I take on a small number of projects alongside my CTO role at Upwex, which keeps the bar high for what I commit to. The best first step is a short email describing what you're building.

Three formats: project-based delivery with a written scope, a fractional tech-lead role (part-time, ongoing), or a focused architecture audit. Long-term contracts are possible when the product is interesting.

Central European time (Portugal). That gives full overlap with European teams and comfortable morning overlap with US East Coast. Async-first communication works best either way.

Yes – legacy rescue is a specialty. I've migrated large AngularJS platforms to modern Angular and untangled codebases past 100k lines. The process starts with a read-only audit week, then a prioritized plan before any rewrite talk.

It depends on the team you'll hire, not fashion. My defaults: Next.js or React for most web products, Angular for large enterprise teams that value convention, React Native when web and mobile share a domain, NestJS + MongoDB on the backend.

Both. I can ship a product end-to-end alone – architecture to store review – or embed into your existing team as a lead: reviews, mentoring, hiring loops and standards included.

Email sinclar96@gmail.com with two paragraphs: what you're building and what's blocking you. You'll get an honest reply – sometimes that's 'you don't need me yet' – and if it fits, a call and a written scope within a week.

Contact

Got an idea?Let's make it live.