Product Engineer (Backend Leaning - Python / FastAPI / SQL)

About MarvelX

MarvelX builds specialized AI agents for complex and highly regulated domains such as insurance claims, compliance, and enterprise support. Our systems run in real world environments where accuracy, reliability, and clarity matter. The market is enormous and we are growing quickly.

We hire Product Engineers, not narrow specialists. You own features end to end: the services and data behind them, the interface in front of them, and the product decisions in between. You will work directly with the founders and engineering leads to shape the systems and surfaces our customers rely on every day. We do not split work across a backend team and a frontend team that throw it over a wall. Everyone here ships across the stack and reasons about the whole product.

This is not a maintenance role. It is a chance to shape a product at an early and meaningful stage. We work on-site in Amsterdam three or more days a week.

Every Product Engineer at MarvelX is fullstack with a lean. This role leans backend.

Where you will spend most of your time

You will own the core APIs, data models, and services that power the platform. You will design clean contracts, model data that holds up under real volume, and keep services fast, observable, and reliable. You will still build the frontend slice that exposes your work and pair with the team on how it feels to use, but the center of gravity is the backend.

What you will work on

• Design and build backend services and APIs using Python and FastAPI

• Model and optimize data in PostgreSQL: schema design, query tuning, transactions

• Add search and analytics where the product needs it (Elasticsearch, Postgres FTS, or equivalents)

• Design data access layers and caching strategies that hold performance at scale

• Build the frontend slice that surfaces your services, in React and TypeScript, with the team

• Write clear, testable code with strong reliability and observability practices

• Shape API contracts directly with the people who consume them

What you bring

• Two to five years building production software, with real depth on the backend

• Strong Python (FastAPI preferred; Flask or Django experience is welcome)

• Solid SQL: schema design, query tuning, transactions

• Comfort owning a service end to end, from contract to deploy to monitoring

• Willingness and ability to work across the stack, frontend included, when the feature needs it

• Product sense: you reason about the user and the outcome, not only the code

• Strength in debugging, testing, and optimizing performance

Bonus points for

• Async Python, caching layers, or message queues

• Search at scale, data engineering, or ETL workflows

• AI-product backends (RAG retrieval, agent orchestration, LLM gateway design)

• Familiarity with Docker and deployment pipelines

• Previous startup experience and comfort in fast moving environments

If you are excited by owning real systems end to end and putting AI into production for users in regulated industries, we would love to meet you.

Location & eligibility

Based in Amsterdam, at least 3 days a week in the office. Work eligibility in the Netherlands required; we are not able to sponsor visas in the Netherlands yet.