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 integral 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.

📌 Backend / API Engineers (Mid to Staff level) – Fintech Platform (Madrid / Hybrid) - E-Frontiers
🏢 E-Frontiers
📍 Madrid