Andrii Nakonechnyi
Andrii Nakonechnyi

Frontend Developer · Kyiv, Ukraine

I turn complex business logic into clear, fast interfaces.

Frontend Developer with 5+ years of experience in production web apps. I build checkout and payment flows, marketing funnels, and POS and retail platforms.

  • Vue
  • Nuxt
  • React
  • Next.js
  • Angular
  • TypeScript
View selected workLinkedIn, opens in a new tabGitHub, opens in a new tab

  • More than 5 years building production web apps

  • FABU: Over 80 percent of product traffic went through the quiz platform

  • FABU: About 15 percent higher conversion from fast funnel iteration and A/B tests

  • FABU: About 20 percent fewer incomplete purchases after the payment flow work

Selected work

Two products, two very different kinds of complexity.

Both are commercial products with private code, so the visuals here are abstract diagrams of the product flows, not screenshots.

Abstract diagram: traffic from Facebook, AppLovin and Google Ads flows through quiz steps with an A and B variant into checkout, upsell and subscription.FACEBOOKAPPLOVINGOOGLE ADSQUIZABA/BFALLBACKCHECKOUTUPSELLSUBSCRIPTION
Illustrative diagram · not the product UI
Case 01FemTech wellness app

FABU

Quiz funnels and payments for a subscription wellness app.

Commercial product · private code

Role
Frontend Developer
Company
w7g (ex SuitsMe), Genesis Tech
Period
Dec 2023 to Oct 2025

FABU acquires users through Facebook, AppLovin and Google Ads traffic. Most of that traffic lands in the quiz platform, and the payment flows turn it into subscriptions.

What I built

  1. Modular quiz platform

    Personalized acquisition flows for Facebook, AppLovin and Google Ads traffic.

  2. Fast experiments

    Fast funnel iteration, A/B testing and systematic hypothesis validation.

  3. Payments and monetization

    Solidgate integration with fallback scenarios, session recovery, upsells and subscriptions.

  4. Compliance and tracking

    GDPR and CCPA compliance and centralized tracking across the funnel.

Results

  • Over 80 percent of product traffic went through the quiz platform

  • About 15 percent higher conversion from fast funnel iteration and A/B tests

  • About 20 percent fewer incomplete purchases after the payment flow work

Stack

  • React
  • Remix
  • TypeScript
  • Tailwind CSS
  • Vite
  • TeamCity
Abstract diagram: a printed receipt at the center, connected to checkout, fiscalization, payments, loyalty, inventory and documents modules.CHECKOUTPAYMENTSLOYALTY & CRMFISCALIZATIONINVENTORYDOCUMENTS
Illustrative diagram · not the product UI
Case 02POS and retail management platform

Posbox

Checkout, fiscalization and back office for retail teams.

Commercial product · private code

Role
Frontend Developer
Company
Checkbox Group
Period
Jan 2026 to Present

A production POS and retail management platform. It covers sales, fiscal operations, inventory, customer management and back-office workflows.

What I built

  1. Checkout and payments
    • Sales and returns
    • Deferred receipts
    • Cashier operations
    • Shift management
    • Receipt recovery
    • Mixed payments
    • Certificates
    • IBAN
    • Monobank integrations
    • Refunds
    • Fiscal cash rounding
  2. Loyalty and CRM
    • Loyalty levels
    • Gifts
    • Client segmentation
    • Bonus flows
    • Client import and export
    • Purchase history
    • Promotions
    • Discounts
  3. Inventory and documents
    • Product catalog
    • Barcode scanning
    • Stock validation
    • Supplies
    • Waybills
    • Manufacturing
    • Online order documents
    • Print-ready templates
  4. Platform health
    • API request handling refactor
    • Localization restructure
    • Unused i18n keys removed
    • Standard frontend workflows
    • Multi-market product behavior

Outcome

A more reliable platform that is easier to maintain, with frontend support for product behavior in more than one market.

Stack

  • Vue.js
  • Nuxt.js
  • JavaScript
  • Pinia
  • Vuetify
  • Pug
  • SCSS
  • Lodash
  • Moment.js
  • Big.js
  • ApexCharts
  • EUSignCP
  • GTM
  • Amplitude
  • Userflow
  • GitLab

Strengths

Where I add the most value.

Six things I do well, each backed by a real project from the last five years.

  • Complex business flows

    Checkout, fiscalization, refunds, subscriptions and loyalty logic, with the edge cases included.

    Posbox · FABU

  • Funnels that convert

    Quiz funnels, A/B tests and payment flows, judged by conversion and completed purchases.

    FABU

  • Scalable architecture

    Clear component structure, standard state management, shared component libraries and UI guidelines.

    Abz.agency · Posbox

  • Performance and rendering

    Faster page loads, better Lighthouse and PageSpeed scores, smooth WebGL canvas rendering across devices.

    Abz.agency · SuitsMe

  • Real-time features

    Video calls, chat, live data updates and collaboration built on WebRTC and WebSocket.

    4HUB · TeamCollab

  • Vue, React and Angular

    Production work in all three: Vue with Nuxt, React with Next.js and Remix, Angular with RxJS and NgRx.

    5+ years

Approach

How I work with product teams.

The frontend is where product decisions meet real users. These habits help me get that part right.

  1. Edge cases are part of the feature

    Returns, recovery and fallbacks get the same care as the happy path.

    In practice

    Posbox: returns, deferred receipts and receipt recovery. FABU: fallback scenarios and session recovery in payments.

  2. Measure, then iterate

    Small changes, clear hypotheses and tracking that shows what actually worked.

    In practice

    FABU: A/B testing and systematic hypothesis validation with centralized tracking, about 15% higher conversion.

  3. Build tools for the whole team

    Good internal tools help product, content and development teams work better together.

    In practice

    SuitsMe: an internal CMS for product, content and development teams. Abz.agency: component libraries and UI guidelines.

  4. Keep the codebase easy to change

    Clear structure and shared conventions make every next feature cheaper.

    In practice

    Posbox: API request handling refactor, localization restructure and standard frontend workflows.

Experience

From agency projects to product platforms.

Four teams since 2021: agency work, a collaboration platform, growth funnels and a mobile game, and now a POS platform.

  1. Jan 2026 to Present

    Checkbox Group

    Frontend Developer · Kyiv, Ukraine

    Posbox · POS and retail management platform

    Read the case

    Core modules for sales, fiscal operations, inventory, customer management and back-office workflows.

    • Vue.js
    • Nuxt.js
    • Pinia
    • Vuetify
    • SCSS

  2. Dec 2023 to Oct 2025

    w7g (ex SuitsMe), Genesis Tech

    Frontend Developer · Kyiv, Ukraine

    FABU · FemTech wellness app

    Read the case

    Modular quiz platform, fast funnel experiments and payment flows with Solidgate.

    • React
    • Remix
    • TypeScript
    • Tailwind CSS

    SuitsMe · Mobile game

    An internal CMS that improved collaboration between product, content and development teams. Responsive web game interfaces with WebGL-based canvas rendering, smooth performance and consistent visuals across devices.

    • Vue.js
    • TypeScript
    • Vuex
    • Vuetify
    • Tailwind CSS
    • Vite

  3. Aug 2022 to Nov 2023

    GetWin

    Frontend Developer · Kyiv, Ukraine

    4HUB · Team collaboration platform

    Video calls, chat and real-time collaboration, so teams can work without third-party tools. File management with upload progress and activity monitoring that reduced upload errors and prevented data loss. Task scheduling, Kanban boards and analytics dashboards.

    • React
    • TypeScript
    • Redux
    • WebRTC
    • WebSocket
    • Chart.js
    • Jest

    TeamCollab · Internal admin portal

    An admin panel for users, files and projects, with role-based access control, real-time data updates and user activity analytics.

    • Angular
    • TypeScript
    • RxJS
    • NgRx
    • Angular Material

  4. Aug 2021 to Jul 2022

    Abz.agency

    Frontend Developer · Kyiv, Ukraine

    Agency projects

    Frontend architecture and standard state management across projects. Initiated component libraries and internal UI guidelines that cut development time for new projects. Built SPAs, server-rendered sites, admin panels, mobile apps and browser extensions, and improved load time, Lighthouse and PageSpeed scores.

    • React
    • Vue.js
    • Angular
    • Next.js
    • TypeScript
    • Cypress

Skills

Stack and tools.

Vue and React are my main tools. I have also built an internal admin portal in Angular.

  • Vue.js

    3+ years

  • Nuxt 3

    In production

  • React

    Next.js and Remix

  • Angular

    RxJS and NgRx

Frameworks

  • Vue.js
  • Nuxt.js
  • React
  • Next.js
  • Remix
  • Angular
  • React Native (Expo)

Languages

  • TypeScript
  • JavaScript
  • HTML5
  • CSS3

State and data

  • Pinia
  • Vuex
  • Redux
  • Redux Toolkit
  • RTK Query
  • NgRx
  • RxJS
  • REST APIs
  • WebSocket
  • WebRTC

Styling and UI

  • Tailwind CSS
  • SASS/SCSS
  • CSS Modules
  • Styled Components
  • Vuetify
  • Material UI
  • Angular Material
  • Bootstrap
  • Storybook
  • Figma

Testing

  • Jest
  • React Testing Library
  • Vue Test Utils
  • Cypress
  • Jasmine
  • Karma

Build and delivery

  • Vite
  • Webpack
  • Git
  • GitLab
  • Bitbucket
  • GitHub Actions
  • Bitbucket Pipelines
  • TeamCity

Product analytics

  • GTM
  • Amplitude
  • Userflow
  • Chart.js
  • ApexCharts

Also worked with

  • Node.js
  • Express.js
  • Socket.IO

Contact

Let’s talk.

The quickest way to reach me is LinkedIn or Telegram. My public code is on GitHub.

Kyiv, Ukraine