I’m Nikolai MelnichenkoFront‑end developer based in Lisbon
I build React and TypeScript front‑ends that stay easy to change
- Shared UI
- Product screens built on the shared component library and its SCSS/BEM structure, which every app on the platform uses.
- Payments
- The payment system on a fintech product, and a third-party payment widget set up for each brand.
- Performance
- Code splitting, lazy loading and bundle analysis, plus Core Web Vitals work on Next.js.
- Releases
- I run the release cycle for my team and wrote the branching and code-style rules it follows.
Stack
Every day
- React 19
- TypeScript
- JavaScript
- Next.js
- SCSS / BEM
- TanStack Query
- Vitest
- Git
Also used in production
- Angular 20
- RxJS
- NgRx
- Redux Toolkit
- MobX
- Emotion
- react-aria
- Custom Elements
- Shadow DOM
- Nx
- Vite
- Webpack
- Storybook
- MSW
- Node.js
- Express
- socket.io
- Zod
- Docker
From personal projects
- Playwright
- Cypress
- Astro
Used daily, output always reviewed
- Claude Code
- GitHub Copilot
- ChatGPT
Experience
Jun 2024 – Present
Current role
Front-End Developer
BrainRocket
- Built product features on the shared UI component library and the SCSS/BEM structure behind it, which every application on the platform uses.
- Built and maintained per-country versions of the product on top of that library. Layout and content differ from country to country, so each one is its own app in the monorepo.
- Set up a third-party payment widget for each brand: configuration, loading it on the page and handling its events.
- Spent over a year on the Angular 20 side of the platform with RxJS, NgRx and SSR over Express, inside an Nx monorepo.
- Expanded automated test coverage with Vitest, React Testing Library and MSW, and cut page load times with code splitting, lazy loading and bundle analysis.
- Release Captain for my team, with full ownership of the release cycle. Wrote the release, branching and code-style conventions the team works to.
Nov 2023 – Jun 2024
Front-End Developer
REnumber Lab
- Led a complete redesign of a marketplace platform on React, Next.js and TypeScript, from front-end architecture through delivery.
- Developed the admin panel and the client-facing front-end for a business SMS messaging product.
- Integrated front-end features with Node.js, Express and .NET back ends, and took requirements and demos directly with client stakeholders.
Oct 2022 – Nov 2023
Front-End Developer
NumFin Global
- Built and optimized React, Next.js and TypeScript applications for a financial analytics product, with Redux and MobX holding application state.
- Dashboards and interactive charts over 60,000+ stocks from 70 exchanges. Shipped the payment system and the advertising integrations on the same product.
- Worked on SEO and Core Web Vitals across the Next.js application, on rendering, metadata and page speed.
Jun 2022 – Oct 2022
Front-End Developer
Self-employed
- Delivered web projects end to end, from Figma layouts to deployed responsive sites, with React, TypeScript, SCSS and BEM. Completed an intensive front-end program in five months instead of the standard nine.
Before front-end: 2016 to 2022
Jun 2021 – Jun 2022
Python Developer
Self-employed · Remote
- Built e-commerce functionality with Python and Django, and containerized a Django REST API with Docker.
2016 – 2022
Petroleum Engineer
Oil and gas companies · Russia
- Delivered the full design, construction and operation cycle for fuel depot sites, coordinating contractors, budgets and regulatory approvals.
Education
2016 – 2019
Tyumen State Oil and Gas University
2012 – 2016
National Mineral Resources University
Languages
- English Professional working
- Russian Native
- Portuguese A2, learning
Let's talk
Hiring, a contract, or a second opinion on a front-end that has got away from you.