Full Stack Engineer - Knowledge Base Team

Country

IT STARTS HERE

Santander (www.santander.com) is evolving from a global, high-impact brand into a technology-driven organization, and our people are at the heart of this journey. Together, we are driving a customer-centric transformation that values bold thinking, innovation, and the courage to challenge what’s possible.

This is more than a strategic shift. It’s a chance for driven professionals to grow, learn, and make a real difference.

Our mission is to contribute to help more people and businesses prosper. We embrace a strong risk culture and all our professionals at all levels are expected to take a proactive and responsible approach toward risk management.

Our Chief Data & Artificial Intelligence Officer (CDAIO) division is building a world-class AI & Data team to make a difference in the lives of over 170 million people worldwide, through one of the largest banks in the world.

We are undergoing one of the biggest transformations in our history and technology is at the heart of our strategy. Join our team to play a part in one of the most important technological projects for the financial sector in the world.

Our mission is to contribute to helping more people and businesses prosper. We embrace a strong risk culture and all our professionals at all levels are expected to take a proactive and responsible approach toward risk management.

THE DIFFERENCE YOU MAKE

• CDAIO / AI TECH is looking for a Full Stack Engineer based in Madrid to join the Knowledge Base team.
• You will build and operate secure, scalable applications, APIs, and user experiences that transform enterprise data into trusted knowledge for RAG, GraphRAG, semantic search, and AI agents.
• Working with AI, Data, Cloud, DevOps, Product, and Security teams, you will deliver production-grade capabilities at enterprise scale. Key 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.

WHAT YOU'LL BRING

Our people are our greatest strength. We value diverse perspectives and empower individuals to make an impact.

Professional Experience

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

Education

BSc or MSc in Computer Science, Software Engineering, or a related field, or equivalent practical experience. (Required)

Languages

Spanish proficiency. (Required)

High level of English. (Preferred)

Hard Skills

• Strong Python skills and experience with FastAPI, Django, or Flask. (Required)
• Experience with React, TypeScript, JavaScript, HTML, and CSS. (Required)
• Strong knowledge of APIs, microservices, distributed systems, security, testing, CI/CD, and observability. (Required)
• Hands-on AWS, Docker, Kubernetes, and infrastructure-as-code experience. (Required)
• Knowledge of RAG, embeddings, vector search, reranking, grounding, and evaluation. (Required)
• Experience with relational, document, vector, graph, or search databases. (Required)
• Knowledge of knowledge graphs, GraphRAG, agent frameworks, Amazon Bedrock, or MCP. (Preferred)

Soft Skills

• Strong problem-solving, ownership, and end-to-end delivery skills.
• Clear communication and effective collaboration with technical and non-technical stakeholders.
• Pragmatic judgment balancing speed, quality, security, reliability, and cost.

WE VALUE YOUR IMPACT

Your contribution matters, and it’s recognized. You can expect a fair, competitive reward package that reflects the impact you create and the value you deliver. But we know rewards go beyond numbers.

We’re enable our teams to go beyond through global opportunities and broad career paths.

Flexibility that works. Enjoy a hybrid working models—some days remote, some days onsite with your team—along with flexible hours.

Learning for life. Access hundreds of courses on our platforms, including exclusive access to our global learning space: SantanderOpen Academy (www.santanderopenacademy.com)

Competitive rewards. Receive a highly competitive salary with performance-based bonuses, motivating you to keep growing with us.

Financial advantages. Benefit from preferential banking terms, special interest rates on loans, life insurance, and more.

Your health is our priority. Through BeHealthy, our global wellness programme, we promote Holistic wellbeing.

We know family is everything. That’s why we offer childcare support and family-friendly programmes tailored to each life stage.

Always by your side. Get access to Santander Contigo, our program for employees and their families offering legal, emotional, and administrative advisory services.

Extra benefits. Gym/WellHub membership, medical centers in some of our facilities, meal subsidy, parking, shuttle service from various points in Madrid, as well as exclusive discounts and offers for Santander employees. And that’s only the beginning—we’ll tell you more when you join!

We’re here to keep you motivated, help you reach your goals, and celebrate your progress, every step of the way.

We make recruiting decisions based on your experience and skills. We value your passion to discover, invent, simplify, and build.

The personal data you provide as well as any data generated during the selection process are confidential and will be processed by Open Digital Services, S.L. with registered office at Plaza de Santa Bárbara 2, 28004 (Madrid), Madrid, Spain for the sole purpose of managing your participation in the selection processes and, where appropriate, to formalise your recruitment.

For further information about your rights and data protection, please read the Open Digital Services Privacy Policy applicable to this type of data processing.

LOCAL COMPLIANCE

Santander is proud of being an organization where there are equal opportunities regardless of age, gender, disability, civil status, race, religion or sexual orientation. We are committed to providing an inclusive and accessible application process for all candidates.

WHAT TO DO NEXT

If this sounds like a role you are interested in, then please apply.

READY TO TAKE THE NEXT STEP IN YOUR JOURNEY?