AI Engineer

About the company

At Fitted, we help early-stage startups build teams that truly fit their product, culture, and stage.

We're currently working with a Madrid-based AI startup building infrastructure to unlock value from unstructured data at scale. Their platform combines LLMs and proprietary models to process, understand, and extract insights from complex documents — used by enterprise clients across finance, legal, and public sectors.

They're a small, highly technical team, now entering a stage where the product is gaining traction and needs to scale reliably in production environments.

About the role

As an AI Engineer, you'll help build and scale the core AI systems behind the product — working across the full lifecycle, from experimentation to production.

You'll work closely with a small, highly technical team, contributing to both the development of the system and how AI capabilities are translated into real product features.

In the short term, a big part of the work will focus on making existing systems more robust and scalable — improving model performance, refining pipelines, and ensuring reliability in real-world usage.

What you'll do

• Design and improve pipelines for processing and understanding large volumes of unstructured data
• Work with LLMs and embeddings to build and refine production-ready systems
• Improve and scale existing infrastructure, ensuring reliability and performance
• Deploy and monitor models in production environments
• Collaborate closely with product to turn AI capabilities into usable features
• Contribute to technical decisions as the system evolves
• Take ownership of key parts of the pipeline, improving them over time

Who you are

Must-haves:

• 3+ years of experience in ML Engineering, Applied AI, or similar roles
• Strong Python skills and experience with modern ML frameworks (e.g. PyTorch, HuggingFace)
• Hands-on experience working with LLMs, embeddings, or similar technologies
• Experience deploying and maintaining models in production environments
• Solid understanding of system design, performance, and reliability in real-world applications
• Comfortable working in early-stage environments with evolving systems and priorities

Nice-to-have:

• Experience working with document processing (OCR, layout analysis, etc.)
• Familiarity with vector databases or retrieval-based systems
• Experience with cloud infrastructure and containerized environments
• Interest in building production systems beyond experimentation

What's in it for you

• Hybrid work model (Madrid, 2 days/week in the office)
• Salary: €55,000 – €75,000 depending on experience
• A key role in a growing early-stage company with real product traction
• High ownership and impact from day one
• The opportunity to work on real-world AI systems at scale