Senior Full Stack Engineer - AI, RAG & Cloud (Madrid)

Santander; Madrid; Hybrid; EUR 90,000 - 130,000; Full time

Benefits offered by this job

Hybrid work model

Santander Open Academy access

Competitive rewards

BeHealthy wellness program

Childcare support

Meal subsidy

Gym/WellHub membership

Job summary

Santander is seeking a Senior Full Stack Engineer based in Madrid to design and operate secure, scalable applications and APIs for the Knowledge Base Platform, collaborating with AI, Data, Cloud, DevOps, Product, and Security teams.

You will work on production-grade capabilities for RAG, GraphRAG, semantic search, and AI agents, using FastAPI, React, Python, AWS, Docker, Kubernetes, and infrastructure-as-code, in a regulated enterprise environment with hybrid work arrangements.

Qualifications

• 5+ years in full stack, backend, cloud, platform, or AI engineering.
• Experience building and operating production-grade distributed systems, APIs, or cloud applications.
• Hands-on experience with LLM applications, RAG, semantic search, or intelligent automation.
• Experience in a regulated enterprise environment (preferred).

Responsibilities

• Design and build full stack applications, backend services, APIs, and web interfaces for the Knowledge Base Platform.
• Develop data-to-knowledge workflows covering ingestion, chunking, embeddings, metadata, entities, relationships, retrieval, and validation.
• Build RAG and GraphRAG services combining vector search, graph traversal, reranking, grounding, and citations.
• Create 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 strong engineering practices across testing, security, observability, CI/CD, reliability, and cost.
• Collaborate across teams and contribute to technical design decisions and platform evolution.

Skills

Problem-solving

Ownership

End-to-end delivery

Clear communication

Pragmatic judgment

Spanish proficiency

English proficiency

Education

BSc or MSc in Computer Science or Software Engineering

Tools

Python (Strong)

FastAPI

Django/Flask

React/TypeScript/JavaScript

HTML/CSS

AWS

Docker

Kubernetes

Infrastructure-as-code

RAG/GraphRAG

APIs / Microservices

Job description

Santander is seeking a Senior Full Stack Engineer based in Madrid to design and operate secure, scalable applications and APIs for the Knowledge Base Platform, collaborating with AI, Data, Cloud, DevOps, Product, and Security teams.

You will work on production-grade capabilities for RAG, GraphRAG, semantic search, and AI agents, using FastAPI, React, Python, AWS, Docker, Kubernetes, and infrastructure-as-code, in a regulated enterprise environment with hybrid work arrangements.