Sebastian Zelonka

UI Engineer

Pixel-perfect, performant, and accessible products on the web.

01 / Story

I started in graphic and product design, working on research, interaction flows and visual interfaces. Over time I moved closer to implementation because I wanted the final product to preserve the intent and care of the design.

Today I build component libraries and design systems, translate tokens into resilient UI, and help designers and engineers make decisions together. I care about the details that make an interface feel clear, fast and dependable.

  • Clarity first

    Reduce ambiguity in the interface, the code and the conversations around both.

  • Systems over patches

    Create reusable foundations that let product teams move with confidence.

  • Accessibility by default

    Treat inclusive behavior as a core product requirement, not a final check.

02 / Selected work

Vetsource · Kibble design system

From a blank repository to a production component library.

I joined before development began, helped choose the stack and delivery model, and established the component, styling, documentation and publishing foundations used by the team.

Contribution
Foundation → v2.8 era
Focus
Architecture, tokens, React and Storybook
Read the case study

03 / Contact

Let’s make the interface hold up.

If you’re working on a design system, a complex product UI or a team workflow that needs a stronger bridge between design and engineering, I’d be happy to talk.

Design systems · React interfaces · Design tokens · Accessibility · Component APIs · Frontend architecture · Designer–developer workflows

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