Collaborated with the Growth team to design and implement onboarding features that streamlined the transition from free to paid plans, improving user engagement.
Zuzanna ŻołnierowiczSoftware Engineer
Summary
Full-Stack Software Engineer with 5+ years of experience designing and shipping high-traffic e-commerce, SaaS, and medtech products, including leading critical components for Allegro, Poland’s leading marketplace.
Expertly bridges frontend development (React, TypeScript) with robust backend and cloud architecture (Node.js, Python, FastAPI, Docker, Kubernetes).
Deeply proficient in building secure, scalable systems, utilizing modern security standards including OIDC and OAuth2.
Experienced in implementing sophisticated authorization patterns such as RBAC and ReBAC.
Backend expertise extends to utilizing Rust and various SQL databases, including PostgreSQL, demonstrated through advanced personal projects.
Languages
| Language | Level |
|---|---|
| English | C2 |
| Polish | Native |
Skills
Languages & Core Web
HTML, CSS, Sass/SCSS, JavaScript, TypeScript
Frameworks & Libraries
React, Next.js, Node.js, Redux, Zustand, Tailwind CSS, shadcn/ui
Testing
Playwright, Cypress, Jest, React Testing Library
APIs & Build Tooling
REST, GraphQL, Vite, Webpack
Backend & Cloud
Python, FastAPI, Rust, Docker, Kubernetes
Engineering Practices & Tools
Git, GitHub, Responsive Design, Performance Optimization, CI/CD, Agile, Scrum
Design Systems & Accessibility
Accessibility, WCAG, Storybook, Design Systems
Experience
- Architected and maintained reusable components for the seller dashboard on Poland’s leading B2C e-commerce platform, improving UI consistency and performance.
- Led the frontend development of a critical component adopted by thousands of sellers, ensuring scalability and seamless integration.
- Implemented process optimizations that boosted internal team efficiency, reducing development cycles and improving operational workflows.
- Advanced the Storybook-driven design system and accessibility (WCAG) standards for the seller dashboard, working within Agile/Scrum and CI/CD workflows.
- Managed the frontend infrastructure for the testing platform, delivering robust and responsive user interfaces.
- Partnered with backend engineers, designers, and the web platform team to ship interface updates, fostering cross-functional collaboration and rapid iteration.
Engineered high-impact websites for global brands, including British American Tobacco, Halfords, and GSK, leveraging Adobe Experience Manager in a collaborative team environment.
Tumor3D
Jul 2020 ‐ May 2021Web Developer- Developed advanced medtech user interfaces using React, and built and deployed backend services on PaaS platforms for seamless application functionality.
- Managed full-stack responsibilities — UI development, backend integration, access control for project tools, and on-site software deployments — ensuring operational reliability.