Oleksa Tyshchenko

Senior Frontend / Full Stack Developer

Oleksa Tyshchenko

10+ years building low-code platforms, back-office systems and AI-powered products.

  • Remote, EU and US hours, open to relocation
  • Open to full-time and part-time contracts
  • B2B through a Ukrainian sole proprietorship
Portrait of Oleksa Tyshchenko

About

I own architecture and performance on large codebases, and run the code review that keeps them maintainable. Most of what I ship is infrastructure other teams build on: low-code platforms, back-office systems, document management, e-commerce. React, Next.js and TypeScript on the front, Node.js and PostgreSQL behind it, with LLM features in the recent products.

What I've owned

  • Designed the DSL behind a low-code reporting platform, so analysts could write their own formulas instead of filing tickets.
    Grammar, editor and evaluation: a parser built with Chevrotain and Lezer, wired into a CodeMirror editor with completion and inline errors.
  • Worked directly with clients in the EU and the US, with no manager in between.
    Contract work, not a staff role.
  • Owned the frontend architecture of that platform: a widget system configured at runtime.
    Every table, chart and text block is defined by the user, over data read from their own databases, with archive creation and PDF export on top. Custom-built drag-and-resize and undo/redo for performance, react-dnd for page ordering and smaller block moves.
  • Built payments and subscriptions from the store receipt through to the renewal job.
    Receipt verification, webhooks, background jobs for renewal and expiry, and PostgreSQL access rules with logging that never writes a token.
  • Took LLM features from prototype to production, inside real product flows, not a demo chatbot.
    Retrieval over the product's own documents, streaming responses, tool calling and agent-style flows, routed through OpenRouter rather than tied to a single vendor.
  • Kept large tables and charts responsive on codebases too large for one engineer to hold in full context.
    Virtualised the big tables, split and lazy-loaded the routes, trimmed the bundle, and cut repeat GraphQL round trips with fragment-level caching.
  • Set up the code review process, and mentored the developers who joined after.
    Wrote the specs the code was built from, and the shared AI coding rules and prompts the team worked to.

Beyond the Code

Most of my career has been remote, working with German, American, Israeli and Ukrainian teams. The same sentence carries different weight depending on who says it: direct feedback that is normal in one team reads as rudeness in another. Erin Meyer's "The Culture Map" is good on this. Knowing that early stops you reading a blunt sentence as a personal problem.

I like difficult problems and play too much Dark Souls. My approach to both is the same: understand how something works before trying harder.

Outside work: manga, long walks and tea. Tea is the only skill on my LinkedIn that was endorsed without me asking.

Skills

  • Frontend
    React · Next.js · TypeScript · GraphQL · Apollo Client · PWA
    · JavaScript · HTML5 · CSS3 · SCSS · CSS Modules · styled-components · Ant Design · Storybook · React Router
  • State
    Redux · Zustand · React Query
    · React Context · Redux-Saga
  • Backend
    Node.js · Express · PostgreSQL · NestJS · TypeORM · REST · API design · WebSockets · Redis
    · Apollo Server · type-graphql · Axios · Nodemailer
  • AI & LLM
    LLM APIs · RAG · Prompt Engineering · AI Agents
    · OpenRouter
  • Tooling
    Docker · AWS (Cloud Essentials) · Jenkins · Git · ESLint
    · GitHub Actions · Webpack · Vite · Prettier · Jest · Vitest · React Testing Library · Enzyme · Figma · Jira · Scrum
  • Libraries
    CodeMirror · Lezer · Chevrotain · Lexical · Chart.js · react-dnd · react-window · D3.js · Lodash · Dexie · Puppeteer

Experience

6 roles · 2015 - 2026

Project
Web and PWA products built with React, Next.js and TypeScript, with backend services and AI-powered features. Ran in parallel with my last months at eTeam.
Result
Owned monetisation end to end, and put the product's first LLM features into production.
Scope

Built product features end to end: paywalls and in-app purchases, offline-friendly mobile-first PWAs with push notifications, and parts of a code editor UI (editing, tabs, file tree, live preview).

Backend in NestJS and Express with REST and GraphQL: payments and subscriptions with store receipt verification, webhooks and background jobs for renewal and expiry, PostgreSQL with safe logging and access rules.

LLM features in production: RAG retrieval, streaming responses, tool calling and agent-style flows, with the prompt design behind them. Wrote the spec before the code and kept both in sync.

Stack
  • TypeScript
  • React
  • Next.js
  • PWA
  • Node.js
  • NestJS
  • GraphQL
  • REST
  • PostgreSQL

Project
nedyx - a low-code platform for business reporting, built by a small international team.
Result
Shipped the widget system, undo/redo, archives and PDF export that the platform's reporting runs on, plus its own functional language.
Scope

Supported and developed the product in React, TypeScript, Node.js, GraphQL and Apollo. Built a dynamic widget system with full visualisation control, large tables, charts and a text editor, reading data from external databases for many users.

Stack
  • React
  • TypeScript
  • GraphQL
  • Apollo Client
  • Node.js
  • TypeORM
  • type-graphql
  • PostgreSQL
  • styled-components

Project
Three applications for LinkSquares: contract lifecycle and legal project management.
Result
Delivered three LinkSquares applications; the dynamic form and table layer became the base the later features were built on.
Scope

Built the logic for rendering dynamic and asynchronous forms, tables and components, plus PDF editors, working from Figma and a kanban board. Used React with hooks, GraphQL, Apollo Server, Redux, Saga, Ant Design, Ramda and several form libraries, alongside my own utilities.

Stack
  • React
  • TypeScript
  • GraphQL
  • Apollo Server
  • Redux
  • Redux-Saga
  • Ant Design
  • Ramda

Project
A dynamic site generator, mostly back office and admin logic. Alongside it, an online store for recreation events and a TED-style speaker platform in London.
Result
Delivered the client side and the back office of a generator that builds and runs other sites.
Scope

Email templates and business logic across a large admin panel, with tables and charts for creating dynamic pages, forms, info blocks and galleries.

Stack
  • JavaScript
  • SCSS
  • Axios
  • REST

Project
An introductory frontend course.
Result
Took a group of 25 beginners from nothing to working HTML, CSS and Git.
Scope

Lectures, practicals and homework review across the full course.

Stack
  • HTML5
  • CSS3
  • Git

Project
The company site and product pages, including Family Tree Maker.
Result
Kept the site current through product launches, adding the pages and questionnaires each one needed.
Scope

Built new page blocks and questionnaires for each product launch.

Stack
  • HTML
  • CSS
  • JavaScript
  • jQuery

Project
Part-time work through FL.ru and Upwork.
Result
Delivered complete sites and mobile versions for clients I found and managed myself.
Scope

Everything from individual page components to full sites and mobile-version updates.

Stack
  • HTML
  • CSS
  • JavaScript
  • jQuery

Project
Radioecological and chemical pollution monitoring of water bodies, alongside graduate school and the first years of web work.
Result
Published research on water pollution monitoring.
Scope

Monitoring and analysis of pollution data, with ArcMap for the spatial work.

Stack
  • ArcMap
  • Data analysis

Education

  • MSc in Computer Science, AI & Machine Learning

    2025.09Present

    Neoversity IT University

    Ongoing, alongside full-time work: machine learning, neural networks, statistics and algorithms.

    Machine learning · Neural networks · Algorithms & data structures · Python for data · Statistics · Research methods

  • Postgraduate studies, Environmental Safety

    20122016

    National Academy of Sciences of Ukraine

    Ran in parallel with research work at the Academy: pollution monitoring, data validation and published papers.

    Research design · Data quality & validation · Technical writing · ArcMap / GIS

  • Master's degree, Project Management

    20112012

    National University "Kyiv Aviation Institute"

    Organised student conferences - the first time I had to plan work for people other than myself.

    Project management · Planning & estimation · Risk management · Global sourcing · Stakeholder communication

  • Bachelor's degree, Hydrometeorology

    20072011

    Taras Shevchenko National University of Kyiv

    Four years of physics, statistics and modelling systems that never repeat exactly. Played chess for the university team.

    Data analysis · Statistical modelling · Scientific method · GIS · Large datasets · Self-directed learning

Certifications

  • FrontendExpert Certificate

    AlgoExpert · certificate.algoexpert.io

  • AlgoExpert Certificate

    AlgoExpert · certificate.algoexpert.io

  • English C1 Advanced

    EF SET · cert.efset.org

  • AWS Cloud Technical Essentials

    Amazon Web Services · coursera.org

Contact

Tell me what you are working on and how I can help.

Contacts

I usually reply within one business day.