Product Engineer (Backend Leaning)

MarvelX AI; Amsterdam; On-site; EUR 70,000 - 100,000; Full time

Job summary

MarvelX AI in Amsterdam is seeking a Backend Engineer to design core APIs and data pipelines that power our AI platform. You will work closely with founders and engineering leads to shape services, ensuring fast, reliable data processing and clear interfaces.

We value strong Python skills (FastAPI preferred), deep SQL knowledge, and experience with Elasticsearch. This role offers a fast-paced startup environment with impactful, production-ready systems.

Qualifications

• Two to four years of production backend experience.
• Strong Python skills (FastAPI preferred).
• Deep understanding of SQL, schema design, queries, and transactions.
• Experience with Elasticsearch, mappings, and performance tuning.
• Ability to design reliable, structured REST APIs.
• Familiarity with authentication and data handling.

Responsibilities

• Design and build backend services and APIs using Python and FastAPI.
• Create and optimize database models and queries in PostgreSQL.
• Implement and tune search and analytics with Elasticsearch.
• Design data access layers and caching strategies for scale.
• Collaborate with frontend and AI teams on clean API contracts.
• Write clear, testable code with reliability and observability.

Skills

Python

SQL

REST APIs

Async programming

Caching

Testing

Debugging

Data pipelines

Data modeling

Distributed systems

Tools

PostgreSQL

Elasticsearch

Docker

FastAPI

Python

Job description

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

We are searching for a Backend Engineer who enjoys working close to the data and creating systems that are fast, stable, and thoughtfully structured. You understand how to design services that move and transform data cleanly, and you care about readability as much as performance.

In this role you will collaborate directly with the founders and engineering leads to shape the core APIs and data pipelines that power our platform. If you like solving intricate problems and building tools others rely on every day, this is a strong fit.

This is not a maintenance role. It is an opportunity to help shape a product at an early and meaningful stage. If that sounds exciting, we would love to talk.

Mission

As Backend Engineer, you will design and build the foundational services behind MarvelX. This includes clean API design, efficient data access layers, and search capabilities that scale. You will work with SQL and Elasticsearch at significant volume, use Python and FastAPI to structure services, and ensure our AI systems have the right data with low latency and high reliability.

What you will work on

• Design and build backend services and APIs using Python and FastAPI
• Create and optimize database models and queries in PostgreSQL and other relational systems
• Implement and tune search and analytics capabilities with Elasticsearch
• Design data access layers and caching strategies that maintain performance at scale
• Collaborate with frontend and AI engineering teams to define clean and intuitive API contracts
• Write clear, testable code with strong reliability and observability practices
• Contribute to internal tooling and pipelines that support our data driven products

What you bring

• Two to four years of experience building production backend systems
• Strong Python skills (FastAPI preferred, experience in Flask or Django is also welcome)
• Deep understanding of SQL including schema design, query tuning, and transactions
• Experience with Elasticsearch including mappings and performance tuning
• Ability to design reliable and well structured REST APIs
• Familiarity with authentication, permissions, and structured data handling
• Strength in debugging, testing, and optimizing performance
• Experience with async Python, caching layers, or message queues
• Understanding of data engineering or ETL workflows
• Familiarity with Docker and deployment pipelines
• Previous startup experience and comfort working in fast moving environments

If you are excited by building real systems that power AI in production, we would love to meet you.