Senior Full-Stack Engineer

Project overview

This recruitment process is conducted on behalf of our client.

Own and ship full-stack features for a subscription platform used by e-commerce businesses. You'll work in a small team in Poland, close to product and the founders.

About the role

A seed-stage B2B SaaS company is building subscription infrastructure for e-commerce: billing, checkout and developer tools. They need a full-stack engineer who owns features from idea to release. You'll work across frontend and backend, talk to designers and founders directly, and help shape the architecture as the product grows.

• Build and ship full-stack features in TypeScript, with React on the frontend and Node.js on the backend.
• Own features end to end: clarify requirements, propose an approach, build, test, release and check the impact.
• Build merchant-facing subscription, billing and checkout flows that are clear and reliable.
• Improve the developer-facing side of the product: APIs, docs, integrations, onboarding and error messages.
• Turn Figma designs into clean, accessible UI and suggest practical UX improvements.
• Keep the architecture simple, observable and maintainable. No over-engineering.
• Do code reviews, write automated tests and keep documentation useful.
• Use AI coding tools where they save time or improve quality.
• Fluent Polish and residence in Poland.
• 5+ years of professional software engineering experience, mostly in product or SaaS companies, not only agencies or consulting.
• Strong TypeScript and Node.js in production, with features used by real customers.
• Production experience with React.
• Experience taking at least one customer-facing feature from requirements to release.
• Comfortable working from Figma designs.
• Able to work independently in an early-stage team without detailed specs.

Nice to have

• Next.js, or Vue and Nuxt.
• Fastify, Express or NestJS.
• Payments or subscriptions: recurring billing, payment providers, invoicing, proration, dunning.
• E-commerce: Shopify, WooCommerce, Magento or headless commerce.
• Public APIs, SDKs, webhooks or developer documentation.
• Startup experience, especially in teams under 200 people.
• Hands-on use of AI and LLM tools (Cursor, Copilot, Claude, OpenAI).

Project details

• Start: ASAP
• Location: Warsaw, Cracow, Lodz, Wroclaw