Backend Engineer

MarvelX AI; Amsterdam; On-site; EUR 50,000 - 70,000; Full time

Job summary

A technology company in Amsterdam is seeking a Backend Engineer to build robust backend services and APIs. Ideal candidates thrive on creating high-performance systems and have solid experience in Python, SQL, and ElasticSearch. Join a fast-paced environment and contribute to impactful AI solutions.

Qualifications

• 2–4 years of experience developing production-grade backend systems.
• Strong command of Python with a preference for FastAPI.
• Excellent understanding of SQL and relational database systems.
• Experience working with ElasticSearch and query optimization.

Responsibilities

• Design and build backend services and APIs using Python and FastAPI.
• Implement and optimize database models and queries using PostgreSQL.
• Collaborate with frontend and AI engineers to design clean APIs.
• Write clear, testable code ensuring reliability through observability.

Skills

Python (FastAPI preferred)

SQL (query optimization, schema design)

ElasticSearch

REST APIs design and implementation

Debugging and performance optimization

Tools

PostgreSQL

Docker

Job description

Backend Engineer at MarvelX AI

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About MarvelX

MarvelX is building highly specialized AI agents for the most complex, heavily regulated industries. Think insurance claims, compliance, support. Automated by AI that actually works in the real world. The opportunity is massive, and we’re moving fast.

We’re looking for a Backend Engineer who thrives on building robust, high-performance systems that move data efficiently and reliably. Someone who understands the balance between speed, scalability, and clarity: and who can turn complex data flows into clean, production-grade services. You’ll work directly with our founders and tech leads to design and implement the APIs and data pipelines that power our AI systems. If you like working close to the data and architecting clean interfaces for complex problems: you’ll love this role. This isn’t a maintenance job. It’s an early seat on the rocket ship. If that sounds like your kind of challenge, let’s talk.

Responsibilities

• Design and build backend services and APIs using Python and FastAPI.
• Implement and optimize database models and queries using PostgreSQL and other relational systems.
• Work with ElasticSearch to enable fast, relevant search and analytics capabilities.
• Design efficient data access layers and caching strategies for performance at scale.
• Collaborate with frontend and AI engineers to design clean, intuitive API contracts.
• Write clear, testable code and ensure reliability through robust error handling and observability.
• Help shape internal tools and pipelines that support our data-driven products.

Qualifications

• 2–4 years of experience developing production-grade backend systems.
• Strong command of Python (FastAPI preferred; Flask/Django acceptable background).
• Excellent understanding of SQL (query optimization, schema design, transactions).
• Experience working with ElasticSearch: queries, mappings, and performance tuning.
• Proven ability to design and implement reliable, well-structured REST APIs.
• Familiarity with authentication, permissions, and structured data management.
• Strong debugging, testing, and performance optimization skills.

Bonus

• Experience with async Python, caching layers, or message queues.
• Knowledge of data engineering principles or ETL design.
• Familiarity with containerization (Docker) and deployment pipelines.
• Startup experience: comfortable building fast and shipping often.

Seniority Level

Mid-Senior level

Employment Type

Full-time

Job Function

Engineering and Information Technology

Industries

Technology, Information and Internet

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