Senior Fullstack Engineer

Kunya; Warszawa; On-site; PLN 835,865 - 1,063,829; Full time

Job summary

Kunya in Warsaw is hiring a Senior Fullstack Engineer to build AI-native product experiences across the stack in a hybrid setup.

You will own features from concept to production, collaborating with design and product, and improving performance and velocity across the stack.

The role emphasizes fast iteration, ownership, and contributing to an engineering culture while working asynchronously and in person in Warsaw.

Qualifications

• 2+ years building production software across frontend and backend.
• Experience with modern web apps and backend services.
• Own problems end to end in a fast-moving environment.
• Experience with APIs, databases, performance, debugging in production.
• Strong written and verbal communication.

Responsibilities

• Build features across frontend, backend, APIs, and supporting systems.
• Partner with design and product to ship ideas from concept to production.
• Improve reliability, speed, and developer velocity across the stack.
• Help simplify AI and media workflows for users.
• Shape architecture and technical choices with practical execution.
• Contribute to engineering culture through code review and ownership.

Skills

Frontend & Backend

Web Applications

APIs & Databases

Production Debugging

Ownership & Velocity

Communication

Job description

# Senior Fullstack EngineerFull-timeWarsaw, Poland · Hybrid$220,000–$280,000/yr## About the role### RoleKunya is building an all-in-one AI platform: chat, images, video, voice, workspaces, and agents. We're hiring a **Senior Fullstack Engineer** to help us ship fast across the stack and build AI-native product experiences that feel seamless to users.This role is based in **Warsaw** with a **hybrid** setup. We're looking for someone who's comfortable moving between focused independent execution and in-person collaboration.### What you'll do* Build product features across frontend, backend, APIs, and supporting systems* Partner with design and product to take ideas from concept to shipped experience* Improve reliability, speed, and developer velocity across the stack* Help make complex AI and media workflows feel simple on the surface* Shape architecture and technical choices with a bias toward practical execution* Contribute to a strong engineering culture through code review and ownership### Why this role mattersThe interface for software is changing. We believe people will spend less time operating software and more time directing outcomes. You'll help build the systems that make that shift real.### How we work* Small team, big scope* High ownership and low bureaucracy* Async-first, with hybrid time in Warsaw* Fast iteration on real product problems## What we're looking for### What we're looking for* 2+ years of experience building production software across frontend and backend* Strong experience with modern web applications and backend services* Good judgment on product tradeoffs, architecture, and shipping velocity* Experience with APIs, databases, performance, and debugging in production* Ability to own problems end to end in a fast-moving environment* Strong written and verbal communication### You may be a fit if you* Like building across boundaries instead of staying in one lane* Care about user experience as much as implementation details* Prefer ownership, clarity, and speed over layers of process* Want to work at the edge of AI product development* Have launched your own product, service, or side project — we value founders and builders who have taken something from idea to real users### Nice to have* Experience with AI products, multimodal systems, or agent workflows* Experience in startups or small high-performing teams — or as a founder* Experience improving engineering quality through mentorship or systems thinking## Benefits & perks### What you get* Competitive salary* Equity upside* Hybrid work setup in Warsaw* Real ownership and visible impact* A chance to help define how AI-native software gets built### The environment* Ambitious but grounded* Fast-moving but thoughtful* High standards without corporate overhead