AI Engineer

About Mafer

At Mafer we are building an AI data platform for R&D teams in formulation industries: flavors & fragrances, food & beverage, cosmetics, personal care, home care and specialty chemicals. We structure the molecular and formulation data that today lives across instruments, spreadsheets and lab notebooks, and turn it into systems that accelerate analysis, formulation and regulatory work.

We are a small, highly technical team of engineers and scientists, working from our office in Barcelona and backed by tier-1 investors. Everyone here works close to customers: you are either building or selling.

The role

At Mafer we are building an operating system for R&D in flavors, fragrances, food and beverage, and cosmetics. The platform processes complex data from Excel macros, instrument outputs, regulatory PDFs, and expert knowledge. We deploy AI engineers to clients to build and integrate the system into their existing workflows.

What you'll do

• Work directly with client technicians to understand their workflows and data, then build and deploy solutions.
• Co-develop the platform: data ingestion from proprietary formats, spreadsheets and regulatory documents; ERP, LIMS and PLM integrations; Postgres and vector search; knowledge bases, agents and ML models.
• Build specialized modules for chromatography analysis, formulation optimization and regulatory systems.
• Dedicate 10% of your time to long-term research projects.
• Own client relationships and modules directly, without intermediaries.

What we look for

• A strong software engineering foundation: clean, tested Python code, and the ability to ship independently.
• Real database experience: schema design, query optimization, migrations and non-standard data. Postgres required.
• LLM expertise in retrieval, agents and evaluation, with sound judgment about which tool fits each problem.
• A scientific mindset and a technical background in mathematics, physics, engineering, computer science or data science.
• Comfortable facing clients, fluent in Spanish and English.
• 2–3 years shipping AI software to production.

Nice to have

• Model training or fine-tuning experience.
• A chemistry or scientific data background.

What we offer: a €5,000 relocation bonus and help finding housing near the office; work with leading companies in the beauty and formulation industries; a small, highly technical team with an MIT-trained CTO and PhDs; €2M pre-seed from K Fund, 4Founders and notable angels; and the flexibility to move between client deployments and deep technical work.

Hiring process

1. Apply below — we read every application and reply if there's a potential fit.
2. A 30-minute conversation with Fer (CEO) to get to know each other and align expectations.
3. A technical interview with Marc (CTO), around one hour.
4. Two days working on-site with us at the office in Barcelona, on a real Mafer problem: you see how we work and we see how you work.
5. We move fast: we aim to decide within three days of the last conversation.