Job ID: 744000153443026

Lead Senior Backend Engineer (m/f/d)

A Coruña, Bilbao, Gijón, Granada, Madrid, Reus, Seville, Valencia

Professional

Regular

T-Systems Iberia

Your Task

We are looking for a senior backend engineer with strong system design skills and experience building production infrastructure. This role involves architecting and maintaining backend platform services behind AI inference endpoints - a multi-tenant system handling authentication, API key management, usage metering, billing and request proxy. This is a high-ownership role where you will shape architecture decisions, raise the bar of engineering quality and build systems that are performant, secure and observable at scale. You'll collaborate with experts in AI infrastructure and data engineering to build robust, secure, and efficient systems that scale to millions of requests.
Responsibilities
- Design and build core platform services: API gateway, authentication, authorization, key rotation, and multi-tenant isolation
- Design, implement,



and optimize APIs and backend systems using Python frameworks such as primarily FastAPI (or Flask, or Django)
- Architect and implement usage metering, billing integration, and rate limiting for inference endpoints
- Build and maintain scalable, fault-tolerant microservices for data processing and AI integration
- Build and operate a high-throughput proxy/routing layer for AI model serving traffic
- Collaborate with cross-functional teams to design system architecture and ensure seamless system interoperability
- Design telemetry and observability into the platform from the ground up — structured logging, distributed tracing, metrics, and alerting
- Implement robust CI/CD pipelines, monitoring, and observability for high-performance production systems
- Drive technical decisions on architecture, data modeling, and technology choices
- Identify performance bottlenecks and drive improvements in reliability, scalability, and latency
- Establish engineering

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