Hi, my name is
Dmytro Kosianchuk
Fintech & enterprise SPAs — Vue 3, TypeScript, real payments and compliance-heavy UIs. I optimize for speed, clarity, and maintainability.
Pixel-level UI, production-grade engineering
Kyiv · remote-friendly. I ship Vue / Nuxt SPAs for payments, documents, and internal tools — profiling before spinners, strict TypeScript, and code written for the next teammate, not just the demo.
Technologies I work with
⚡ Frontend Core
🛠️ State & Tools
🎯 Craft & Quality
Work Experience
Frontend Developer
Checkbox.ua
- Fintech SPAs (Vue 3, Nuxt, TS): payments, admin, internal tools
- Complex forms, transactions, defensive UI for sensitive flows
- Core Web Vitals: checkout page LCP 4.2s → 1.8s
- Shared components for checkout & dashboards; close work with backend/QA
Frontend Developer
EPAM Systems
- Enterprise SPAs for international clients (retail, media)
- Accessibility (WCAG 2.1 AA), i18n, strict TS standards
- Component library with 20+ typed components and full docs
- Comprehensive test coverage: unit, integration, E2E
Layout Developer
Freelance
- Semantic HTML/CSS, responsive marketing and small-business sites
- JS for UI, validation, simple backend hooks
- Implementation from handoffs and client feedback
Featured Projects
DubiDoc — E-Document Signing Platform
Frontend Developer · Checkbox.ua
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Problem
Ukrainian businesses were drowning in paper. They needed a secure B2B platform to create, route, and legally sign documents in one place — with multi-party approval chains, strict audit trails, and zero room for trust failures.
What I Did
Owned the full document lifecycle UI: drag-and-drop signing order builder, real-time participant status timeline, inline PDF viewer with annotation support. Designed defensive UX for every edge case — expired signatures, network drops, declined approvals. Built reusable form components shared across the product suite.
Result
Shipped the entire signing journey on schedule. Became Checkbox's first standalone B2B SaaS product, opening a new market segment and positioning the company in Ukraine's digital compliance space.
First B2B SaaS at Checkbox · Multi-party e-signatures · Launched 2024
B2B e-document platform with drag-and-drop signing chains, PDF preview, real-time status. Became Checkbox first standalone SaaS product.
First B2B SaaS at Checkbox · Multi-party e-signatures · Launched 2024
Checkbox PRRO — Fiscal Cash Register
Frontend Developer · Checkbox.ua
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Problem
Ukraine legally mandated software fiscal registers for all retailers. Businesses needed a cashier UI so fast and reliable that it could survive slow connections and handle hundreds of transactions per shift — with absolutely zero tolerance for fiscal data errors.
What I Did
Built the cashier-facing interface: receipt creation, returns, and shift management. Implemented optimistic UI so interactions felt instant regardless of connection speed. Handled complex multi-rate tax logic and deeply integrated with the State Tax Service (DPS) API. Covered all transaction edge cases with bulletproof error handling.
Result
Rolled out to thousands of business locations across Ukraine. Zero critical fiscal data transmission failures post-launch. PRRO became the flagship Checkbox product and the company's primary recurring revenue source.
Thousands of active locations · 0 critical fiscal errors · Flagship revenue product
Government-compliant cashier UI. Optimistic UI, DPS API. Thousands of locations across Ukraine, zero critical errors after launch.
Thousands of active locations · 0 critical fiscal errors · Flagship revenue product
Avid MediaCentral — Newsroom Platform
Frontend Developer · EPAM Systems
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Problem
Broadcast newsrooms worldwide needed a modern web interface for real-time multi-source media monitoring. The existing solution was slow, visually inconsistent, and failed WCAG accessibility requirements — blocking adoption in regulated markets.
What I Did
Developed the live monitoring dashboard: real-time aggregated news feed, multi-source filtering, inline editable data grid. Led all accessibility work — semantic HTML, ARIA patterns, full keyboard navigation — until the platform passed a WCAG 2.1 AA audit. Built a 20+ component TypeScript library shared across 3 product teams.
Result
Platform shipped on time and deployed to broadcast newsrooms globally. WCAG 2.1 AA audit passed on the first review — no rework cycle. Shared component library reduced duplicate implementation effort by an estimated 60% across teams.
WCAG 2.1 AA on first review · 20+ typed components · Broadcast clients worldwide
Enterprise newsroom platform for Avid Technology. Real-time media feeds, WCAG 2.1 AA, 20+ shared components used by global broadcast clients.
WCAG 2.1 AA on first review · 20+ typed components · Broadcast clients worldwide
Retail Platform — E-commerce Redesign
Frontend Developer · EPAM Systems
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Problem
A major European retailer's e-commerce platform had accumulated years of tech debt: inconsistent UI across markets, broken accessibility, and performance bottlenecks that were directly contributing to cart abandonment at checkout.
What I Did
Led the full front-end overhaul. Migrated core pages from a legacy template-based system to a structured Vue.js SPA. Built a new component library with strict TypeScript, implemented i18n across 5 locales, and overhauled the asset delivery pipeline — lazy loading, code splitting, modern image formats — targeting measurable Core Web Vitals gains.
Result
Core Web Vitals improved across all key conversion pages. Unified design system shipped consistently across 5 locales. New architecture reduced new feature delivery time dramatically — teams could ship in days what previously took weeks.
Core Web Vitals improved · 5 locales · SPA migration on schedule
E-commerce SPA migration for a major European retailer at EPAM. Vue.js, 5 locales, Core Web Vitals uplift, component library from scratch.
Core Web Vitals improved · 5 locales · SPA migration on schedule
Key Accomplishments
Performance Boost
LCP 4.2s → 1.8s on checkout: splitting, lazy routes, lean validation.
Bug Reduction
Transaction state machine (WebSocket + fallback) — stuck-payment tickets ↓80%.
Component Library
Typed Vue 3 kit: 20+ components to PDF signatures — full TS.
Codebase Migrated
Vue 2 + Vuex → Vue 3 + Pinia; TS coverage 40% → 85%.
Let's build something great
Open to senior frontend roles and freelance projects. I respond within 24 hours.
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