Full-stack Developer (React + .NET)

SINGU•Paris Township, MI

1d•Hybrid

About The Position

We're looking for a Full stack Developer to join our product team, with a focus on React and working knowledge of C# and .NET. Our frontend rewrite in React is about to start, and you'll be part of it from day one. You'll also deliver features end to end, from the REST API and PostgreSQL through to the UI. We estimate the split will be roughly 80% front-end and 20% back-end. You'll collaborate with the Team Lead, Product Manager and Product Designer to build reliable, secure, high-quality software. Code reviews, solid testing and AI-assisted development are part of how we work every day. This is a hybrid position (3 days per week from our Cracow or Warsaw office).

Requirements

3+ years of commercial React development with strong TypeScript
Working C# knowledge: you can work in an existing codebase, ship smaller backend changes and grow from there
Proven experience integrating and designing REST APIs
Working knowledge of PostgreSQL
A genuine testing habit: unit and integration tests as standard practice
Comfort participating in code reviews and giving direct, useful feedback
Ownership of delivered features, from technical design to production and support
Practical experience with AI-assisted development tools, and the judgment to critically assess what they produce
Communicative English (B2+): technical specs, tickets, documentation
Communicative Polish (B2+): the team works in Polish internally

Nice To Haves

Experience improving test automation and local development environments
PostgreSQL query optimization (indexes, execution plans)
Docker and cloud (AWS)

Responsibilities

Build user interfaces in React and TypeScript as a core contributor to our frontend rewrite
Turn designs into responsive, accessible and performant UI, built on maintainable code
Contribute to shared components and our design system
Build and extend backend features in .NET 10 and C# 14
Design and develop REST APIs that are consistent, secure and well documented
Work with PostgreSQL database structures and help optimize queries, indexes and performance
Treat unit, integration and end-to-end testing as a core part of development, not an afterthought
Participate in code reviews with clear, constructive feedback
Write clean, secure, maintainable code aligned with our standards and best practices
Use AI tools (Cursor, Claude Code or similar) to accelerate development, code analysis and refactoring
Evaluate the correctness, quality, security and performance of AI-generated code before it ships
Take part in product discovery and feature specification, as well as technical breakdown and estimation before development starts
Work within GitHub and CI/CD to deliver features reliably and on time, and own them through to production
Collaborate closely with the Team Lead, PM and Designer day to day and actively participate in Agile ceremonies
Share knowledge and support your teammates