Eryk Kozyra

Senior Frontend Developer, React & Next.js

Warsaw, Poland (CET)
4h daily overlap with US Eastern
Contract, 20–30 h/week · English C1
[email protected]
linkedin.com/in/eryk-kozyra
+48 795 703 347

Release cycle after a shared dependency update, 30 projects

6–8 h30 s

Main-screen load time on large healthcare datasets

30 s2 s

New B2B customer acquisition after registration flow redesign

+35%

Six years building React and Next.js products for European companies, currently as an independent contractor. My work is the frontend that shows up in business numbers. Conversion flows, load performance, and the tooling that removes hours from every release. I also set the AI development standards for my current team.

Experience

Jun 2023present

Inter Cars

Senior Frontend React & Next.js Developer

Next.jsTypeScriptTurborepoGraphQLElasticsearchStorybook
  • Consolidated ~30 separate frontend projects into a single Turborepo monorepo. Releasing after a shared dependency update dropped from 6 to 8 hours of manual per-project deploys to one 30-second pipeline run
  • Audited and redesigned the B2B registration flow, contributing to a 35% increase in acquisition of new B2B customers
  • Owned research and rollout of AI-assisted development standards for the frontend team: tool evaluation, code review requirements for generated code, and handling of proprietary code in prompts
  • Led frontend delivery for 15+ websites across Inter Cars subsidiaries in Europe, coordinating with backend, DevOps and design
  • Merged 7 separate Polish market projects into a single platform, unifying navigation, content model and deployment
  • Delivered the new intercars.com corporate site end to end, from architecture to launch
  • Implemented Elasticsearch indexing for editorial and news content, replacing slow database queries with sub-second search across all sites
  • Built and maintained the shared component library powering all group sites, bringing it to WCAG compliance across 15+ properties
  • Mentored mid and junior developers through code review, pair programming and individual growth roadmaps
Jul 2022May 2023

Genome

React & React Native Developer

ReactElectronReact NativeAzure Healthcare API
  • Rebuilt the desktop application from scratch as v2.0 in React with Electron, cutting main-screen load time for large Azure Healthcare API datasets from up to 30 seconds to about 2
  • Built the data visualisation layer with charts and graphs generated from the collected datasets, turning large API payloads into readable summaries
  • Applied the same data-loading and rendering optimisations to the React Native mobile app on iOS and Android
Aug 2021Jun 2022

Leocode

Frontend React Developer

ReactNext.jsTypeScript
  • Built the playlist and live-streaming web experience for one of Denmark's largest radio broadcasters
  • Delivered a webinar platform handling live sessions and on-demand playback
  • Built a job board platform with search, filtering and employer dashboards
May 2020Jul 2021

Confilogi

Frontend Developer, then Team Lead

ReactNext.jsSCSS
  • Promoted from junior to lead a team of five frontend developers within 11 months, selected as successor by the outgoing lead
  • Delivered a high volume of advertising landing pages under tight campaign deadlines, with a focus on pixel-accurate implementation and load performance
  • Introduced shared patterns and code review practice to a team with no senior members

Selected work

Inter Cars
intercars.comCorporate site for a distributor operating in 15+ European markets
Inter Cars
intercars.com.plPolish market site built by merging 7 separate projects into one platform
Leocode
bliskopracy.plJob board with faceted search, applications and employer dashboards
Independent
radcaprawny-jb.plContent site for a law firm with service taxonomy, blog and SEO. Delivered end to end as sole developer

Skills

Core
React, Next.js, TypeScript, React Native, Electron
Data & API
GraphQL, REST, Elasticsearch, SSR and caching strategies
Tooling
Turborepo, Storybook, Tailwind, Vercel, CI pipelines, Claude Code, Cursor
Testing
Playwright, Jest, unit and E2E testing
Practice
Design systems, WCAG accessibility, performance optimisation, SEO, AI-assisted development standards

Education

2017–2021
BEng Computer Science, University of Technology and Humanities in Radom. Specialisation: web applications