Backend / API Engineers (Mid to Staff level) – Fintech Platform (Madrid / Hybrid)

We’re hiring 4 Backend Engineers (Mid, Senior, and Staff levels) to join a high-impact API Platform team building scalable, self-serve infrastructure used by both customers and internal product teams.

This is a rare opportunity to join a fast-growing fintech environment where the API is a top business priority and sits at the core of the company’s platform modernisation strategy.

Location

Madrid (Hybrid: 4 days in office / 1 day remote)

Salary

€40K – €90K + bonus + benefits (depending on experience level: Mid / Senior / Staff)

🧩 About the team

You’ll join an API Platform team focused on:

• Building a modern, scalable API surface used by external clients and internal teams
• Creating self-service capabilities, including instant API credential provisioning
• Launching and expanding a new API sandbox environment for clients
• Improving performance, observability, reliability, and developer experience
• Building foundations for AI-driven workflows via API integrations (MCP / agentic interfaces)
• Supporting platform modernization and service decomposition at scale

The API is evolving into a product in itself, with strong visibility across engineering and the business.

🛠️ Tech environment

You don’t need to know everything, but experience in similar ecosystems is key:

• Backend: Python, Django, REST APIs
• Data: PostgreSQL, Redis
• Infrastructure: AWS, Docker, Kubernetes, Terraform
• Identity / access: IAM concepts (Keycloak or similar is a plus)
• Strong engineering fundamentals: system design, OOP + functional design, clean architecture
• CI/CD, observability, monitoring, and production ownership mindset

What you’ll do

Depending on your level, you will:

• Design and build scalable backend services and APIs
• Own services end-to-end (“you build it, you run it”)
• Contribute to architecture decisions via RFC process
• Improve platform reliability, latency, and developer experience
• Mentor more junior engineers (Senior+ levels)
• Help shape a modern platform used at global scale

🧠 What we’re looking for

• Strong software engineering fundamentals (algorithms, design patterns, architecture)
• Experience building production-grade distributed systems
• Comfortable working in cloud-native environments
• Strong communication skills in English (international teams)
• Ownership mindset and ability to thrive in ambiguity
• Fintech experience is highly valuable

Growth & impact

• First 3–6 months: contribute to building new platform components from scratch
• 12 months: ownership of a key platform area + influence across teams
• Clear performance framework and quarterly career development reviews
• High visibility role in a strategic engineering initiative

🤝 About E-Frontiers

We are a specialist tech recruitment partner working with leading product companies and fintech organisations across Europe. We focus on connecting strong engineering talent with high-impact roles where they can grow and build meaningful products.

If you’re interested or know someone who could be a fit, feel free to reach out directly or send your CV.