You’re the kind of developer who writes the failing test first - and feels genuinely uneasy shipping anything that isn’t covered. TypeScript is your native language, async/await is muscle memory, and you think in queues, schemas, and edge cases. You don’t just call an LLM API; you design the prompts, wire up the tools, validate the structured output, and ship AI features that actually hold up in production. Where others see a messy legacy codebase, you see a system you can understand, test, and improve - one green run at a time.
We’re looking for a Backend Developer (m/f/d) to help us scale the engine behind AMALYTIX - the SaaS platform Amazon sellers and vendors rely on every day. You’ll work on data pipelines that crunch millions of marketplace records, on the AI agents that automate listing optimization and reporting, and on the APIs that power our frontend. With a strong test culture, short feedback loops, and real ownership, your code makes a measurable difference from day one.
What you can expect
- Building robust backend services: You design and ship features across our Node.js/TypeScript backend - REST APIs (Express, TypeBox), background workers, and integrations with the Amazon SP-API and Advertising API. You write code that’s typed, tested, and built to last.
- Test-driven by default: TDD isn’t a buzzword here - it’s how we work. You write tests first, keep our Mocha/Chai suites green, and treat a failing test as the fastest path to a correct solution. You care about coverage that means something, not coverage for its own sake.
- Shipping AI features that work: You build and refine our LLM-powered agents (OpenAI, AWS Bedrock, Google Gemini) - designing prompts, wiring up function-calling tools, enforcing structured output, and managing rate limits. You know the difference between a demo and a production-ready AI feature.
- Working with data at scale: You model and query data across MongoDB (Mongoose) and PostgreSQL (Drizzle), write efficient aggregations, design indexes that hold up under load, and keep our message-driven architecture (RabbitMQ consumers and publishers) idempotent and resilient.
- Owning quality end to end: You review pull requests, care about clean architecture, and help us pay down legacy while keeping the lights on. You ship, you monitor (Datadog, Sentry), and you fix what you broke.
What you bring
- Solid backend experience: You’ve built and maintained production backend systems with Node.js and TypeScript. You’re comfortable with async patterns, REST APIs, relational and document databases, and message queues.
- Heavy test-driven development experience: This is a must. You have real, hands-on experience practising TDD, you write clean and meaningful tests, and you can argue convincingly why a test belongs (or doesn’t). A codebase without tests makes you nervous.
- Strong AI skills: This is a must, too. You’ve built features on top of LLMs - prompt engineering, tool/function calling, structured outputs, and the practical realities of latency, cost, and reliability. You use AI tooling to make yourself faster and you know where it helps and where it doesn’t.
- A pragmatic, ownership mindset: You make decisions, you take responsibility, and you’d rather ship a tested, well-scoped solution than a perfect one that never lands. You read code as carefully as you write it.
- Communication skills: You explain technical trade-offs clearly, give and receive honest code review, and collaborate well in a small, fast-moving team - in English (German is a plus).
- Digital native: You automate what can be automated, integrate new technologies into your daily work, and pick up new tools and domains quickly.
What we offer you
- Real impact: A small team, no bureaucracy, and a product used by thousands of Amazon sellers. Your code ships fast and matters.
- Modern stack: TypeScript everywhere, native ESM on Node 24+, Drizzle, TypeBox, a real test culture, and AI deeply embedded in the product - not bolted on.
- Flexible working hours: Plan your day to fit your rhythm. Work efficiently and make time for your personal life.
- Remote work: Work from anywhere within Germany, or up to 4 weeks a year from another EU country.
- Vacation: 30 vacation days per year to relax, travel, and recharge.
- Technical equipment: We provide modern tools and hardware for remote and on-site productivity.
- Training and growth: Time and budget to learn new things, attend conferences, and sharpen your craft.
- Team culture: Strong team spirit, regular offsites, honest communication, and great coffee from our Lelit Bianca.
- Health & fitness: €50 monthly Urban Sports subsidy to keep your body and mind in shape.
