Aleksi Puttonen contributed to both the polarsource/polar and facebook/stylex repositories by focusing on front-end component development and design-system integration. He addressed a mobile Safari chart overflow issue in polarsource/polar by ensuring ChartContainer defaults to 100% width when unspecified, improving mobile responsiveness. In facebook/stylex, he built a Storybook integration example that demonstrates how StyleX can be used with React components such as Button and Card, leveraging Babel, ESLint, PostCSS, and Vite for a robust documentation environment. His work emphasized reusable patterns and cross-repository UX alignment, reflecting a thoughtful approach to scalable, maintainable front-end architecture.