Lead Senior Backend Engineer

production infrastructure, The role involves owning and architecting the backend platform behind our AI inference endpoints - a multi-tenant system handling authentication, API key management, usage metering, billing, and request proxy services that enable high-availability, data-intensive AI-powered solutions. You will shape architecture decisions, raise the bar of engineering quality, and build systems that are performant, secure, and observable at scale. Responsibilities * Design and build core platform services: API gateway, authentication, authorization, key rotation, and multi-tenant isolation. * Architect and implement usage metering, billing integration, and rate limiting for inference endpoints. * Build and operate a high-throughput proxy/routing layer for AI model serving traffic. * Design telemetry and observability - 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 standards for the backend codebase: testing, code review, CI/CD, and deployment practices, ensuring best practices for security, compliance, and maintainability across the API lifecycle. * Collaborate closely with the ML infrastructure team to integrate with model serving systems (e.g., NVIDIA Dynamo, vLLM, SGlang, TensorRT-LLM). Qualifications * Degree in Computer Science, Software Engineering, or equivalent professional experience. * 5+ years of experience building and operating backend systems in production, with meaningful scale and focus on API design and high-scale production environments. * Strong proficiency in Python and at least one systems-oriented language (Go, Rust, Java, C++), with deep knowledge of asynchronous programming and modern Python tooling. * Proven experience designing and maintaining REST APIs (REST, gRPC, WebSockets, SSE, Webhooks) in production environments and the trade-offs between them. * Solid understanding of distributed systems - consistency, fault tolerance, concurrency, performance and networking, data pipelines, and performance optimization. * Experience designing authentication/authorization systems (OAuth2, JWT, API key management, RBAC/ABAC). * Experience with cloud infrastructure (AWS, GCP, or Azure) and containerized environments (Docker) and orchestration (Kubernetes). * Understanding of database design (SQL, ORMs) and data modeling at scale. * Fluent in English (written and verbal), comfortable collaborating in international teams. Nice-to-have * Experience with high-throughput, low-latency or real-time systems (message queues, event-driven architectures). * Familiarity with generative AI or large language models - integration of AI APIs, RAG workflows, or vector databases.

• Experience with modern DevOps practices, infrastructure as code, GitOps workflows, and observability tools (Prometheus, Grafana, OpenTelemetry). * Exposure to ML serving infrastructure (model servers, GPU scheduling, inference optimization). * Occasional front-end coding when necessary. * Experience in stress/load testing and evaluating performance of production systems. * Strong problem-solving mindset and commitment to code quality and performance excellence. * Track record of improving engineering culture: mentoring junior engineers, introducing better practices, leading technical discussions. Additional Information We offer an international, dynamic, and collaborative environment. Hybrid work model (remote/on-site) with flexible working hours. Growth & Development: customized training access to Coursera, weekly language classes (English, Spanish, German), international mentoring sessions and experience days. Compensation & Benefits: flexible compensation plan (health insurance, meal vouchers, childcare, transport), tel

T-Systems is part of the Deutsche Telekom Group, with around 30,000 employees worldwide. We create technology with purpose to generate a positive impact on society. We trust people: we offer autonomy, continuous support, and a collaborative environment where you can grow without limits. We are one global team, guided by respect, integrity, and a passion for doing better every day. T-Systems is at the forefront of innovation, delivering advanced technology solutions across sectors including automotive, healthcare, and public services. Our AI Foundation Services team builds the platform infrastructure that powers AI inference at scale, including API gateways, authentication, billing, and multi-tenant serving, designing and building high-performance backend systems and APIs that power intelligent applications across diverse industries. Role Overview We are looking for a senior backend engineer, highly skilled Python developer with strong system design skills and, experience building