Senior Product Engineer (Backend Leaning)

Much of this company’s trade execution runs through AI agents - and agents are only as good as the product around them: reliable data, well-designed APIs, and interfaces where the team can review, correct, and approve what an agent proposes before real money and real shipments move. As a Senior Product Engineer, you’ll own business problems end to end - talking to the people who use what you build, deciding with Product what to solve, and shipping the whole slice: data model, services, AI agents, and UI. You’ll work in a domain where prices and stock change daily, supplier data arrives in every format imaginable, and a wrong number costs real money.

What you’ll do

• Own a business problem from first conversation through production - e.g. making supplier pricing reliable from ingestion all the way to the quote a salesperson sends.
• Build backend services for pricing, inventory, orders, and integrations across suppliers, customers, and logistics partners.
• Build the AI agents themselves plus their tools and APIs, with safeguards - idempotency, validation, audit trails, human review where it matters.
• Design the interfaces where commercial teams review, correct, and approve agent proposals.
• Turn messy external data (price lists, datasheets, stock feeds) into data the business can trust.
• Evaluate and monitor LLM-driven workflows in production.
• Lead technical decisions, document trade-offs, and mentor other engineers.
• Help shape hiring - run interviews, help define what good engineering looks like.

Tech stack

Java 21 / Spring Boot 3, Python, LangGraph and LLM APIs (OpenAI, Anthropic, Gemini), PostgreSQL, Kinesis, AWS + Terraform, GitHub Actions, TypeScript / Node.js / Next.js / React. You don’t need all of it on day one - the team leans heavily on AI coding tools and expects you to pick up whatever a given problem needs.

• 5+ years building and running production software with real users and real consequences.
• Strong backend skills at production scale in Java or a comparable language (Kotlin, C#, Go) - willingness to work in Java/Spring Boot specifically.
• Experience designing distributed, event-driven systems with a focus on data correctness and failure modes.
• Solid PostgreSQL and hands-on AWS experience.
• Full-stack delivery capability - your depth is backend, but you can ship a good interface in TypeScript/React when the problem needs it.
• Strong product sense - you ask why before how, talk to users, and turn vague problems into clear plans.
• Comfort in a fast-growing, fast-changing environment.
• A track record of solving business problems, not just technical ones.
• Curiosity and good engineering judgment about LLMs/agents is a must; hands-on experience building with them is a strong plus.
• Bonus: experience in trading, marketplaces, supply chain, fintech, or another domain where data errors cost real money.

Practical details

Berlin, hybrid. English-speaking environment. Learning/development budget included.

A fast-growing, well-funded Berlin-based startup rebuilding B2B procurement from the ground up. This category is a €900B+ market in Europe alone, still run almost entirely by people - four or five intermediaries between supplier and customer, with up to 40% of the margin evaporating along the way. This company is building the alternative: they buy from global suppliers and sell directly to European customers on their own account, running sourcing, pricing, sales, logistics, credit, and financing through AI. One request in, a firm quote back in minutes, delivered on time - no warehouses, no fleet, no inventory risk, every trade pre-sold before it’s bought. They’re also the credit counterparty, scoring and insuring customers in minutes with working capital that’s bank-funded, not equity-funded.

Where they are today: strong triple-digit-million-euro turnover run rate, majority repeat customers, seven live European markets sourcing globally, 80+ people, and a recent well-backed funding round from top-tier European VCs plus bank working-capital facilities.