Senior Full-Stack Engineer (m/f/d)

"Buying Labs is the leading global partner for sourcing and distributing premium consumer goods!"

We're looking for a Senior Full-Stack Engineer (m/f/d) to join our Tech team at our Hamburg headquarters. Our goal is to supercharge how our business works with AI and technology, wherever it makes a real difference. You'll build the systems our teams rely on every day, from internal applications to the data and AI capabilities behind them, and see the impact of your work directly in the business.

This is a role for an experienced engineer who takes real ownership: someone who designs solid systems, builds AI into them where it adds value, and drives their work through to production and real users.

• Own systems end to end: Design, build and run features across frontend and backend, from technical approach through deployment and support in production.

• Build AI into our products: Design and integrate AI-powered features such as structured extraction, classification, automation and agentic workflows. Make them reliable through validation, evaluation and human review where it matters.

• Data modelling and architecture: Build solid data models in PostgreSQL that serve as the foundation for our applications and AI features. Make architecture decisions that keep our systems maintainable as they grow.

• Modern and established codebases: Build new applications on our modern stack, and maintain and modernise our established JavaScript platform, which our teams rely on every day.

• Quality you can stand behind: Write tested, reviewed code and verify your own work before it reaches users. Monitor and troubleshoot production issues.

• Work closely with the business: Understand the processes behind what you build, work directly with our commercial and operational teams, and help shape what gets built and why.

• Raise the bar: Share knowledge,

• 6+ years of professional software engineering experience, with a track record of building and running production applications end to end.

• Proven experience building AI into production systems or applications, for example LLM-based extraction or classification, RAG, or agentic and tool-use workflows. You know how to make AI output reliable through validation, evaluation and fallbacks. Using AI coding assistants alone does not meet this requirement.

• You use AI tools in your daily development work and have solid habits for checking and reviewing what they produce.

• Strong TypeScript and JavaScript, and modern React, including hooks and state management.

• Strong backend experience with Node.js and Express or a comparable framework, REST APIs, and integrating external systems.

• Deep PostgreSQL and SQL skills, with solid data modelling and experience with an ORM or query builder such as Knex, Sequelize or Prisma.

• Comfortable working across both modern TypeScript applications and an established JavaScript codebase.

• Strong quality mindset: automated testing, code reviews, and taking responsibility for what you ship.

• High ownership and drive: you push your work through to done, raise problems early, and don't wait to be told what to do next.

• Clear communication with both technical and non-technical colleagues.

• Bachelor's degree in Computer Science or a related field, or equivalent experience.

• Fluent English required; German is a plus.

• Based in Hamburg or willing to relocate.

Nice to Have

• Depth in LLM tooling: provider APIs (Anthropic, OpenAI, Gemini), agent and tool-use patterns (MCP), and evaluating output quality.

• Vector search (pgvector or similar).

• Product or process awareness: experience understanding how a business works and turning messy processes into structured systems.

• Experience integrating ERPs or operational systems (orders, inventory, master data).

• Our wider stack: Bun, Vite, Redis, RabbitMQ, Docker, GitHub Actions, AWS.

• Observability and product analytics tools (e.g. Sentry, Datadog, PostHog).

• Python for data tooling.

• Background in eCommerce, wholesale or B2B environments.

• An awesome team & great vibes: Work with motivated colleagues in an agile, ambitious, and friendly atmosphere where collaboration and fun go hand in hand with high speed.

• Flat hierarchies & real growth opportunities: Take ownership of your role and develop personally alongside the company. We promote from within and value every voice, regardless of seniority or title.

• Modern workplace & cutting-edge equipment: State-of-the-art office setup including adjustable desks, mobile treadmills, air conditioning, and everything you need to excel in your role.

• Company pension program (bAV): Smart pension plan with a 30% Buying Labs grant on your contribution, investing in your financial future together.

• Corporate Benefits membership: Access exclusive discounts from a wide range of partner brands and retailers.

• Full "Deutschlandticket" coverage: We cover the complete cost (ca. €60/month) so you can travel sustainably and conveniently throughout Germany.

• Free bike options: Choose between a complimentary "Swapfiets" bike (original or deluxe 7) or opt for JobRad bike-leasing with an additional €26/month grant from Buying Labs.

• Complimentary food & beverages: Free Friday lunch in the office, plus organic fruit & vegetables, drinks, snacks, coffee/tea, healthy shots and seasonal treats (e.g. ice cream, soups) throughout the week.

• Personalized workspace setup: €100 welcome voucher to customize and optimize your workspace from day one.

• Refer-A-Friend (employee referral program): You love being part of Buying Labs? Fantastic! Then recommend people from your personal network and receive attractive rewards.

Sounds like a perfect fit? We can't wait to meet you. Apply now and be part of our journey!