Backend Engineer

7 dagen geleden


Amsterdam, Noord-Holland, Nederland Zeno Voltijd

Help build the AI backbone of legal tech. As our Backend Engineer, you'll design and scale backend infrastructure that powers LLMs and intelligent AI agents used across legal workflows.

About Zeno

Zeno is a legal AI startup building the next generation of intelligent software for legal professionals. The legal world runs on documents, context, and nuance — and we're building AI tools that deeply understand that. Our end-to-end platform combines advanced language models, retrieval systems, and document intelligence to support the full legal workflow: from research and drafting to bulk contract review.

We're not just building features — we're rethinking how legal knowledge work is done. Our clients include top-tier law firms (50+ FTE), and we've secured €2M in funding. Everything we build is hosted securely in Europe, fully ISO 27001 certified.

What makes us unique is our approach: no shallow AI integrations, but agentic systems designed for real-world performance and legal-grade reliability. Everything is built in-house by a small team of highly technical founders (backgrounds in AI, theoretical physics, infra), based in Rotterdam.

You'll join us at a pivotal moment. The foundation is there, the traction is real, and we're scaling. As engineer #5 or #6, you'll shape what Zeno becomes — in code, architecture, and culture.

Use AI to help legal professionals think, reason, and draft smarter.

Architect the systems that turn AI into real-world legal tools

Zeno's platform depends on fast, scalable, and secure backend systems to make complex legal workflows usable and intelligent. As a Backend Engineer, you'll take the lead in designing robust API infrastructure that enables our AI agents to reason over legal content, process documents at scale, and deliver precise outputs to our users. This role combines architectural thinking with hands-on development — perfect for engineers who want to shape the core of an AI-first product.

What you'll do:

  • Design and build RESTful APIs (FastAPI) that power our core platform features
  • Integrate backend systems with AI agents, document parsers, and retrieval pipelines
  • Own the backend for core legal workflows: from document upload to AI-generated output
  • Monitor and improve backend performance, reliability, and security
  • Collaborate with AI engineers to align infrastructure with model needs and constraints

What we're looking for:

  • 3+ years of backend experience with Python, ideally using FastAPI
  • Experience with relational (PostgreSQL) and/or graph/vector databases (e.g. GraphDB, Pinecone)
  • Solid understanding of API architecture, service orchestration, and system design
  • Someone who likes to build clean, maintainable systems with real-world usage in mind

What we offer:

  • A unique opportunity to work at a startup that is shaping the future of legal tech
  • The ability to make a direct and tangible impact on the development and growth of our platform
  • An inspiring place to work in an office located at the heart of Rotterdam
  • Collaboration with a top-tier team of engineers, researchers, and entrepreneurs
  • Competitive compensation, including growth and equity opportunities within the company

Recruitment process via Haystack People

Zeno works exclusively with Haystack People to fill these key roles. Haystack helps us connect with engineers who can build exceptional systems and thrive in a culture of autonomy, focus, and momentum. You'll be supported throughout the process — from first intro to final offer — by an experienced consultant who understands both the role and the team behind it. Interested or have questions? Reach out directly to Desley Gontha via d.gontha@haystackpeople.nl or +31 6 28965652

Keywords: Python, FastAPI, REST APIs, LLMs, AI Agents, Langchain, Vector Search, GraphDB, Postgres, Backend Architecture


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