Senior Front-End Engineer · AccentureContract · Apr 2025 - Dec 2025 · 9 mos
Prague, Czechia · Hybrid
• Performed a comprehensive security audit, identified and remediated 87 vulnerabilities, eliminating all security backdoors and implementing safeguards to prevent any data leakage to third parties.
• Conducted accessibility audits and refactored legacy components across key client platforms to achieve full WCAG 2.1 compliance, enhancing user experience and meeting legal obligations.
• Collaborated within an internal team to design and build a React Native workspace-booking application from the ground up, enabling efficient desk reservations in a hybrid work environment.
Senior Full-Stack Engineer · ReliventContract · Nov 2023 - Jan 2025 · 1 yr 3 mos
Warsaw, Poland · Remote
• Enhanced client-side application performance by 68% through the integration of the Konva.js library, addressing rendering inefficiencies, and increasing user engagement by refining data-binding and rendering pipelines.
• Engineered mobile application using React Native, optimizing QR code scanning to rapidly process 100+ tickets in under 60 seconds.
• Designed and implemented a standalone module that offers company investors clear insights into company metrics, which enhanced brand visibility and stakeholder confidence.
React Native Developer · TicketportalContract · May 2024 - Oct 2024 · 6 mos
Prague, Czechia · Hybrid
• Collaborated with backend engineers to design and implement a season‑ticket and subscription management system, enabling flexible packages for specific seasons and streamlining match‑day access for 10 000+ fans.
• Developed a loyalty‑tracking module that enabled fans to monitor their attendance at Sparta matches and earn gifts for frequent visits, boosting repeat attendance by ~20% and improving supporter retention.
• Optimized mobile applications for iOS and Android across multiple device manufacturers (Apple, Google, Samsung, Xiaomi, etc.), reducing average load times by roughly 35% and significantly enhancing user experience.
React Native Developer · Epic Web3Contract · Jun 2023 - Nov 2024 · 1 yr 6 mos
Lisbon, Portugal · Remote
• Collaborated with a small cross‑functional team (backend developer, product owner and designer) to design and build a React Native application connecting Web3 professionals at blockchain conferences worldwide; the app onboarded 500+ users during its first events and facilitated hundreds of connections.
• Integrated the app with the Stripe API, enabling users to purchase in‑app currency and seamlessly perform paid actions; this integration led to a ~30% increase in paid feature adoption.
• Co‑designed the application's architecture alongside the backend developer — spanning frontend, backend, databases and DevOps to ensure scalability and security, supporting thousands of concurrent users without performance degradation.
Full Stack Engineer · EASYCON Solution s.r.o.Full-time · Aug 2022 - Nov 2023 · 1 yr 4 mos
Brno, South Moravia, Czechia · On-site
• Boosted PageSpeed Insights score from 19–33% to 76–83% through deep codebase audits, utilizing tools like Lighthouse and Webpack for caching and asset optimization.
• Provided structured training sessions, mentoring junior team members, and best practices guidance, resulting in faster onboarding, improved code quality, and stronger team cohesion.
• Delivered 12 customer-specific application modules that improved the capabilities of the platform, resulting in increased customer satisfaction and increased revenue.
Blockchain Developer · 482.solutionsFull-time · Apr 2020 - Jun 2022 · 2 yrs 3 mos
Odessa, Ukraine · Hybrid
• Developed a real-time IoT monitoring dashboard using WebSockets for seamless data streaming, integrating device data with blockchain to ensure data immutability and enhance operational transparency for clients.
• Implemented and deployed over 100 unit and integration tests using Jest and Mocha, achieving 90% code coverage and targeting critical functionalities and edge cases, which enhanced code reliability and reduced bugs.
• Optimized the internal UI library with 50+ custom React components using Storybook, improving reusability, reducing development cycles, and enhancing responsiveness, accessibility, and maintainability.