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Hi, I’m Karol, a senior frontend engineer with 9+ years of experience building React/TypeScript apps across SaaS, fintech, and developer tools. I lead modernization initiatives, own feature delivery, and help raise engineering standards. Based in Kraków, I enjoy collaborating with product, UX, and backend teams to ship fast and maintain high-quality interfaces. I work across cross-functional teams to deliver end-to-end experiences, mentor engineers, and shape roadmaps. I thrive on solving complex problems, building scalable frontend architectures, and continuously improving delivery processes.…Hi, I’m Karol, a senior frontend engineer with 9+ years of experience building React/TypeScript apps across SaaS, fintech, and developer tools. I lead modernization initiatives, own feature delivery, and help raise engineering standards. Based in Kraków, I enjoy collaborating with product, UX, and backend teams to ship fast and maintain high-quality interfaces. I work across cross-functional teams to deliver end-to-end experiences, mentor engineers, and shape roadmaps. I thrive on solving complex problems, building scalable frontend architectures, and continuously improving delivery processes.

Karol Bartyzel

Front-End Developer, Full Stack Developer, Web Developer, +2

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Hi, I’m Karol, a senior frontend engineer with 9+ years of experience building React/TypeScript apps across SaaS, fintech, and developer tools. I lead modernization initiatives, own feature delivery, and help raise engineering standards. Based in Kraków, I enjoy collaborating with product, UX, and backend teams to ship fast and maintain high-quality interfaces. I work across cross-functional teams to deliver end-to-end experiences, mentor engineers, and shape roadmaps. I thrive on solving complex problems, building scalable frontend architectures, and continuously improving delivery processes.…Hi, I’m Karol, a senior frontend engineer with 9+ years of experience building React/TypeScript apps across SaaS, fintech, and developer tools. I lead modernization initiatives, own feature delivery, and help raise engineering standards. Based in Kraków, I enjoy collaborating with product, UX, and backend teams to ship fast and maintain high-quality interfaces. I work across cross-functional teams to deliver end-to-end experiences, mentor engineers, and shape roadmaps. I thrive on solving complex problems, building scalable frontend architectures, and continuously improving delivery processes.

Available to hire

Hi, I’m Karol, a senior frontend engineer with 9+ years of experience building React/TypeScript apps across SaaS, fintech, and developer tools. I lead modernization initiatives, own feature delivery, and help raise engineering standards. Based in Kraków, I enjoy collaborating with product, UX, and backend teams to ship fast and maintain high-quality interfaces.

I work across cross-functional teams to deliver end-to-end experiences, mentor engineers, and shape roadmaps. I thrive on solving complex problems, building scalable frontend architectures, and continuously improving delivery processes.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Intermediate

Language

English

Fluent

Polish

Fluent

Spanish; Castilian

Intermediate

Work Experience

Senior Frontend Engineer at Codility

October 1, 2025 - Present

Remote - online technical assessment platform. Led frontend modernization: designed and built features across a 30-person engineering org (grown from 15), shipping features on time; cut column configuration payload from up to 1 GB down to 30–50 MB; used AI-assisted tools to move faster across an 800-person company.

Frontend Engineer at NFT Nerds

June 1, 2022 - August 31, 2023

Remote - real-time blockchain marketing analytics platform. Designed and built most of the frontend for a real-time NFT analytics platform with 10,000+ daily users and market data updating every second. Created 10 pages including trade offer feeds and live blockchain data views, all refreshing live. Sole frontend engineer for 14 months, shipping the first version in 90 days and helping founders shape the road map.

Frontend Engineer at PwC

December 1, 2020 - May 31, 2022

Remote - financial audit platform. Owned frontend delivery for a financial audit platform used by auditors across global PwC markets, within a 15-person team. Reduced technical risk by running 2 proof-of-concept evaluations that shaped key technology and library decisions. Mentored 3 developers and drove sprint planning, improving how consistently the teams shipped across quarterly releases.

Frontend Engineer at ESET

September 1, 2018 - November 30, 2020

Kraków, Poland - internal tooling platform for security engineers. Led full rewrite of a multi-dashboard cybersecurity platform from Angular to React, delivering the entire application for a 15-engineer team. Set engineering standards and internal training, bringing all engineers up to speed on modern React patterns. Built dashboards and permissions panels used daily by 1,000+ security engineers.

Junior Full Stack Engineer at Medius

July 1, 2017 - August 31, 2018

Kraków, Poland - enterprise API invoice automation platform. Delivered 20+ frontend features for an enterprise accounts payable platform used by 3,000+ corporate clients globally. Worked in an 8-person Agile team, collaborating with backend engineers and clients to ship product updates on schedule.