Filip Kalný

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Skills


Languages	English C2 • Czech native TypeScript • JavaScript • HTML • CSS • Bash
Frameworks	Next.js • React • TanStack Start • Effect.ts • Sanity • Strapi • Astro • Express
Libraries	React Hook Form • Zod • React Query • TanStack Table • TanStack Form • GraphQL • Protobuf • Zustand • Tailwind CSS • i18next • Paraglide JS • Socket.io • WebSockets • Emotion • Jest • React Testing Library • Axios • Storybook • Drizzle • TypeORM
Tools	Git • OpenCode • NeoVim • Arch Linux • MacOS • Docker • Figma • Node.js • GitHub • Copilot • Vercel • Nginx • NX • Bun • Ubuntu • TurboRepo • Claude Code • DigitalOcean

Experience

Company	Dates	Role	Project(s)	Technologies
Deutsche Börse	Q1-Q2 2026	Lead Product Engineer	Internal market administration tool	Effect, TypeScript, React, protobuf, WebSockets
Groupon	2023-2025	IC, Tech Lead on Checkout Team	Ecommerce Checkout & Post-purchase experience	Next, React, Typescript, NX, Apollo, GraphQL, Tailwind, Adyen, React Testing Library, Jest, Playwright, Zustand, Storybook
Thimble	2020-2023	Fullstack IC	Circularo mobile web app, Unikol web, Galerie Gema auction site + others	Next, React, Typescript, Tailwind, React Query, Apollo, GraphQL, Socket.io, Emotion, TypeORM, Styled Components, Nodemailer, PostgreSQL
AtomRTC	2019-2020	Frontend IC	LiveSupp customer support live chat, Šetři Chytře utilities comparison calculator	React, Styled Components
Freelance	2017-ongoing	Freelancer	Deskohub cowork, Deskohub bar, Prefilda FF UK + others + misc. consulting/auditing	Bun, Drizzle, Convex, MySQL, Wordpress, PHP, others…

About me

Senior full-stack engineer (7+ years) focused on dependable, observable, and maintainable web products. I specialize in end-to-end type-safe systems and have owned product delivery from analyst input through launch. At Groupon Checkout, my tech lead work centered on technical decisions, implementation quality, and release gating for an initiative that contributed to a double-digit revenue increase.