Senior Backend Engineer for AI Infrastructure & APIs

Deutsche Telekom AG; La Coruña; Hybrid; EUR 90,000 - 110,000; Full time

Benefits offered by this job

Hybrid work model (remote/on-site)

Flexible working hours

26+ vacation days

Job summary

T-Systems Iberia is seeking a Lead Senior Backend Engineer to design and maintain scalable backend platform services behind AI inference endpoints. You will architect multi-tenant systems for authentication, API key management, usage metering, billing, and request proxy.

Responsibilities include building core services with Python (FastAPI), implementing telemetry, security, and CI/CD pipelines, and collaborating with ML infrastructure teams to ensure secure, observable, and high-performance

Qualifications

• Senior backend experience in production scale environments
• Strong knowledge of Python async programming and tooling
• Experience with REST, gRPC, WebSockets, and SSE protocols
• Design authentication and authorization systems and API key management
• Experience with cloud providers and container orchestration (Docker, Kubernetes)
• Active collaboration in international teams

Responsibilities

• Design and build core platform services: API gateway, authentication, key rotation, multi-tenant isolation
• Develop APIs and backends using Python (FastAPI preferred)
• Implement usage metering, billing integration, and rate limiting
• Build scalable microservices for data processing and AI integration
• Operate high-throughput proxy/routing for model serving traffic
• Institute telemetry and observability with logs, traces, metrics, alerts
• Set high engineering standards: tests, CI/CD, deployment
• Collaborate with ML infra to integrate with model serving systems

Skills

Python

FastAPI

REST APIs

Distributed systems

Cloud infrastructure

Docker

Kubernetes

OAuth2/JWT/API keys

AWS/GCP/Azure

SQL/ORM

English communication

Education

Computer Science/Software Engineering degree

Tools

Git

Prometheus/Grafana/OpenTelemetry

Redis

nVidia Dynamo/vLLM/TensorRT-LLM integrations

Job description

T-Systems Iberia is seeking a Lead Senior Backend Engineer to design and maintain scalable backend platform services behind AI inference endpoints. You will architect multi-tenant systems for authentication, API key management, usage metering, billing, and request proxy.

Responsibilities include building core services with Python (FastAPI), implementing telemetry, security, and CI/CD pipelines, and collaborating with ML infrastructure teams to ensure secure, observable, and high-performance