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.📍 LocationMadrid (Hybrid: 4 days in office / 1 day remote)💰 Salary€40K – €90K + bonus + benefits (depending on experience level: Mid / Senior / Staff)🧩 About the teamYou’ll join an API Platform team focused on:Building a modern, scalable API surface used by external clients and internal teamsCreating self-service capabilities, including instant API credential provisioningLaunching and expanding a new API sandbox environment for clientsImproving performance, observability, reliability, and developer experienceBuilding foundations for AI-driven workflows via API integrations (MCP / agentic interfaces)Supporting platform modernization and service decomposition at scaleThe API is evolving into a product in itself, with strong visibility across engineering and the business.🛠️ Tech environmentYou don’t need to know everything, but experience in similar ecosystems is key:Backend: Python, Django, REST APIsData: PostgreSQL, RedisInfrastructure: AWS, Docker, Kubernetes, TerraformIdentity / access: IAM concepts (Keycloak or similar is a plus)Strong engineering fundamentals: system design, OOP + functional design, clean architectureCI/CD, observability, monitoring, and production ownership mindset💡 What you’ll doDepending on your level, you will:Design and build scalable backend services and APIsOwn services end-to-end (“you build it, you run it”)Contribute to architecture decisions via RFC processImprove platform reliability, latency, and developer experienceMentor more junior engineers (Senior+ levels)Help shape a modern platform used at global scale🧠 What we’re looking forStrong software engineering fundamentals (algorithms, design patterns, architecture)Experience building production-grade distributed systemsComfortable working in cloud-native environmentsStrong communication skills in English (international teams)Ownership mindset and ability to thrive in ambiguityFintech experience is highly valuable🌱 Growth & impactFirst 3–6 months: contribute to building new platform components from scratch12 months: ownership of a key platform area + influence across teamsClear performance framework and quarterly career development reviewsHigh visibility role in a strategic engineering initiative🤝 About E-FrontiersWe 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.