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# Backend Engineer - API

- **Company:** SpaceXSI
- **Location:** London, United Kingdom
- **Salary:** £107,000 - £262,000
- **Contract:** Permanent contract
- **Skills:** Application Programming Interfaces (APIs), C++ (Programming Language), Databases, Distributed Systems, PostgreSQL, MongoDB, System Availability, Multi-Agent Systems, Backend, Rate Limiting, Containerization, Kubernetes, Low Latency, SGLang, TensorRT, Vertica, VLLM, Model Inference, Docker
- **Published:** October 14, 2026
- **Apply:** https://www.indeed.com/viewjob?jk=8e3ef371b7afa7da

## About the Role

As an ideal candidate you have a good understanding of how highly scalable and reliable production infrastructure is built. Most of our backend infrastructure is written in Rust. So familiarity with a compiled language such as C++, Rust, or Go is highly beneficial., * Expert knowledge of either Rust or C++

 * Experience in designing, implementing, and maintaining reliable and horizontally scalable distributed systems
 * Knowledge of service observability and reliability best practices
 * Experience in operating commonly used databases such as PostgreSQL, Clickhouse, and MongoDB, * Experience with LLM inference engines and serving frameworks (e.g., SGLang, TensorRT, vLLM)
 * Experience designing or building with agent SDKs and agent orchestration frameworks
 * Experience with Docker, Kubernetes, and containerized applications
 * Expert knowledge of gRPC (unary, response streaming, bi-directional streaming, REST mapping)

## Description

* Build the SpaceXSI API that serves our models to developers worldwide
 * Own the end-to-end system responsible for high-throughput inference, handling billions of tokens per minute with low latency and high availability, including model serving infrastructure, request routing, SDK development, rate limiting, observability, and efficient scaling