Senior Full-Stack Engineer | React & Data Analytics

Remote · Long-term · 5+ years of experience

Karton is a data-driven platform for collectible cards, starting with Pokémon. We’re looking for an experienced full-stack engineer who can design and build the whole product, from polished interfaces to the data systems behind them, and who works directly with the founders.

What you’ll build

• Responsive, high-quality interfaces and analytics dashboards
• Backend systems that integrate multiple external APIs and data providers
• Data pipelines, price aggregation, historical statistics and market analytics
• Scalable databases, automated data processing and reliable production infrastructure

What you bring

• 5+ years of professional full-stack development
• Excellent React, TypeScript, SQL and backend skills
• Strong UI/UX sense, with a track record of polished interfaces
• Extensive production experience with API integrations, data processing and analytics
• Experience with PostgreSQL, Supabase or similar
• The ability to build and run complex applications independently, from start to finish
• Experience working with Claude Code

How to apply

Send us one thing: a link to your personal website or online portfolio.

• It must show at least 10 live websites or web applications that you personally designed and developed.
• GitHub links are not accepted in place of a portfolio.
• No CV, cover letter or explanations needed.

We’ll review every portfolio and reach out to candidates whose design and engineering quality fits what we’re building.

The role

You’ll take ownership of a long-term product build, working side by side with the founders.