Full Stack Engineer - Knowledge Base Team

Description

The company is a large bank in the middle of a major technology transformation, and its AI and Data team in the CDAIO division is building the work that supports it.

The role is a Full Stack Engineer on the Knowledge Base team, based in Madrid. The team turns enterprise data into trusted knowledge for RAG, GraphRAG, semantic search and AI agents.

You will work alongside AI, Data, Cloud, DevOps, Product and Security teams to ship production-grade capabilities at enterprise scale.

Responsibilities

• Design and build full stack applications, backend services, APIs and web interfaces for the Knowledge Base Platform.
• Build the data-to-knowledge pipeline: ingestion, chunking, embeddings, metadata, entities, relationships, retrieval and validation.
• Create RAG and GraphRAG services that bring together vector search, graph traversal, reranking, grounding and citations.
• Build secure integrations and tools for AI agents, including MCP-based interfaces.
• Deliver cloud-native solutions on AWS using containers, serverless and event-driven patterns.
• Apply sound engineering practice to testing, security, observability, CI/CD, reliability and cost.
• Work with other teams on technical design decisions and the evolution of the platform.

Requirements

• 5+ years in full stack, backend, cloud, platform or AI engineering.
• Experience building and running production distributed systems, APIs or cloud applications.
• Hands-on work with LLM applications, RAG, semantic search or intelligent automation.
• A BSc or MSc in Computer Science, Software Engineering or a related field, or equivalent practical experience.
• Spanish at a professional level.
• Strong Python skills and experience with FastAPI, Django or Flask.
• Experience with React, TypeScript, JavaScript, HTML and CSS.
• Strong knowledge of APIs, microservices, distributed systems, security, testing, CI/CD and observability.
• Hands-on experience with AWS, Docker, Kubernetes and infrastructure-as-code.
• Knowledge of RAG, embeddings, vector search, reranking, grounding and evaluation.
• Experience with relational, document, vector, graph or search databases.
• Preferred: experience in a regulated enterprise environment.
• Preferred: a high level of English.
• Preferred: knowledge of knowledge graphs, GraphRAG, agent frameworks, Amazon Bedrock or MCP.
• Problem-solving, ownership and the ability to see work through end to end.
• Clear communication with both technical and non-technical stakeholders.
• Pragmatic judgment that balances speed, quality, security, reliability and cost.

Conditions

Hybrid working: some days remote, some days onsite with your team, with flexible hours.

Based in Madrid.

The company is an equal opportunities employer and is committed to an inclusive, accessible application process.

Benefits

• A competitive salary with performance-based bonuses.
• Preferential banking terms, special loan interest rates, life insurance and more.
• Access to hundreds of courses, including the global the company Open Academy.
• Wellness programme (BeHealthy), childcare support and family-friendly programmes.
• The company Contigo support for employees and their families, covering legal, emotional and administrative advice.
• Gym or WellHub membership, medical centres at some sites, meal subsidy, parking, a shuttle service from various points in Madrid, and employee discounts and offers.