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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Backend Engineer - **Company:** T-Systems Iberia - **Location:** Madrid, Spain - **Contract:** Permanent contract - **Skills:** Java (Programming Language), Application Programming Interfaces (APIs), Artificial Intelligence, Amazon Web Services, Application Integration Architecture, Microsoft Azure, C++ (Programming Language), Cloud Computing, Profiling, Software Quality, Code Review, Continuous Integration, Information Engineering, Database Design, DevOps, Distributed Systems, Django Web Framework, Fault Tolerance, Python (Programming Language), Key Management, Load Testing, OAuth, Performance Tuning, Queueing Systems, Role-Based Access Control, Prometheus, JSON Web Token, Software Engineering, SQL Databases, Web Application Frameworks, WebSocket, AI Infrastructure, Rust (Programming Language), Data Logging, Data Processing, Real Time Systems, Flask (Web Framework), Delivery Pipeline, Large Language Models, Grafana, Generative AI, Backend, Rate Limiting, Fastapi, Event Driven Architecture, Build Management, Kubernetes, Information Technology, Low Latency, Build Tools, Machine Learning Operations, Front End Software Development, TensorRT, Asynchronous Programming, Api Design, Api Gateway, Restful APIs, Grpc, Webhooks, Data Pipelines, Dynatrace, Api Management, Docker, Microservices - **Published:** September 24, 2026 - **Apply:** https://www.adzuna.es/contact-us.html ## About the Role We are looking for a senior backend engineer highly skilled Python Developer with strong system design skills and experience building production infrastructuredeep experience designing, building, and scaling distributed systems and APIs. In this role, YyYou willou will own architect and drive the evolution of the maintain backend platform behind our AI inference endpoints - a multi-tenant system handling authentication, API key management, usage metering, billing and request proxyservices that enable high-availability, data-intensive AI-powered solutions. The role is high-ownership and 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., + Degree in Computer Science, Software Engineering, or equivalent professional experience. + 5+ years of experience building and operatingdeveloping backend systems in production, with a meaningful scale with a focus on API design and high-scale production environments. + Strong proficiency in Python and at least one systems-oriented language (Go, Rust, Java, C++), willingness to work across the current stack which includes Python (FastAPI) - we value the right tool for the jobengineer with deep knowledge of asynchronous programming, modern Python tooling and profiling. + Proven experience designing and maintaining REST APIs (REST, gRPC, WebSockets, SSEIncluding websockets, SSE, Webhooks etc.) in production environments and the tradeoffs 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 containers ized environments (Docker) and orchestration (, Kubernetes). + Understanding of database design (SQL, ORMs etc.) and data modeling at scale. + Fluent in English (written and verbal) and comfortable collaborating in international teams. Nice-to-have requirements: + Experience with high-throughput, low-latency or real-time systems (e.g., message queues, event-driven architectures). + Familiarity with generative AI or large language models (e.g., integration of AI APIs, RAG workflows, or vector databases). + ExperienceKnowledge of in 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) is a plus but not required. + Comfortable occasionally touching or contributing to frontend code 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. ## Description + 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 standards for the backend codebase: testing, code review, CI/CD, and deployment practices.Ensure 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). ## Related Videos - [Exploring the Power of gRPC-Gateway for Writing RESTful Services](https://www.wearedevelopers.com/videos/2072-exploring-the-power-of-grpc-gateway-for-writing-restful-services) - [Keeping applications secure by evolving OAuth 2.0 and OpenID Connect](https://www.wearedevelopers.com/videos/100152-keeping-applications-secure-by-evolving-oauth-2-0-and-openid-connect) - [Docker Compose: Rediscovered](https://www.wearedevelopers.com/videos/1978-docker-compose-rediscovered) - [Inside Bitpanda's Tech Stack: Scaling a European Fintech Leader - Markus Dorner](https://www.wearedevelopers.com/videos/1979-inside-bitpanda-s-tech-stack-scaling-a-european-fintech-leader-markus-dorner) - [Boosting OpenSearch Performance: gRPC Search in Action](https://www.wearedevelopers.com/videos/1964-boosting-opensearch-performance-grpc-search-in-action) - [Shipping Faster with Less: Render on Cloud Hosting, AI Workloads, and the Future of DevOps](https://www.wearedevelopers.com/videos/1894-shipping-faster-with-less-render-on-cloud-hosting-ai-workloads-and-the-future-of-devops) ## Related Articles - [The Most Popular IT Jobs on the Market](https://www.wearedevelopers.com/magazine/376-the-most-popular-it-jobs-on-the-market) - [Top-Paying Tech Jobs (with Salaries)](https://www.wearedevelopers.com/magazine/372-top-paying-tech-jobs-with-salaries) - [Fully Remote Software Engineer Jobs](https://www.wearedevelopers.com/magazine/447-fully-remote-software-engineer-jobs) - [Where To Find Software Engineering Jobs](https://www.wearedevelopers.com/magazine/396-where-to-find-software-engineering-jobs) - [The 12 Best Jobs for Software Engineers](https://www.wearedevelopers.com/magazine/401-the-12-best-jobs-for-software-engineers) - [Find a Developer Job: 12 Best Job Sites For Developers](https://www.wearedevelopers.com/magazine/165-find-a-developer-job-12-best-job-sites-for-developers)