Product AI Engineer - Production-Grade LLM Apps

Pillar; Barcelona; On-site; EUR 55,000 - 75,000; Full time

Job summary

Pillar is building the financial operating system for construction with AI at its core. This role focuses on taking LLMs into production, designing agentic workflows, and creating reliable AI-powered features that scale.

Join a hands-on team moving fast in a startup/scaleup environment to Ship impactful AI products for real customers. Based in Barcelona or Milan, you will own end-to-end AI delivery, work with Mastra, LangChain, and CrewAI, and collaborate with product and engineering to ship

Qualifications

• Experience building LLM-based applications for production, not just prototypes.
• Familiar with agents, tool use, structured outputs, and orchestration.
• Hands-on with RAG, embeddings, vector databases, and retrieval strategies.
• Proficient in SQL and relational databases; strong problem solving.

Responsibilities

• Own AI features end to end, from product problem to production.
• Design and build agentic workflows with orchestration and structured outputs.
• Build and optimize RAG and semantic search pipelines.
• Develop document extraction workflows turning invoices, reports, and forms into structured data.
• Establish observability, testing, and quality checks for AI features.
• Collaborate across our TypeScript stack for product integration.
• Move quickly from ambiguity to working product with pragmatic decisions.

Skills

LLM-based apps

Agents & tool use

Structured outputs

Multi-step reasoning

RAG & embeddings

Vector databases

Retrieval strategies

SQL & relational DBs

Prompt design & evaluation

Startup/scaleup mindset

Clear communication

Tools

Mastra

LangChain

CrewAI

Embeddings

Vector search

Job description

Pillar is building the financial operating system for construction with AI at its core. This role focuses on taking LLMs into production, designing agentic workflows, and creating reliable AI-powered features that scale.

Join a hands-on team moving fast in a startup/scaleup environment to Ship impactful AI products for real customers. Based in Barcelona or Milan, you will own end-to-end AI delivery, work with Mastra, LangChain, and CrewAI, and collaborate with product and engineering to ship