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source · wttj·req · jb_5d9920c150·listed 2d ago

Backend Engineer (API)

xAI·London, United Kingdom·Hybrid·Full-time
Sourced listing · wttjNo salary disclosed
Posted
13 May 2026
via wttj
Type
Full-time
Arrangement
Hybrid
United Kingdom
Deadline
14 June 2026
closes in 30d
compensation · not disclosed
Salary not shared
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Summary

the pitch

Join our team as a Backend Engineer and play a crucial role in building the xAI API that serves our models to developers worldwide. You will own the end-to-end system responsible for high-throughput inference, handling billions of tokens per minute with low latency and high availability. This includes model serving infrastructure, request routing, SDK development, rate limiting, observability, and efficient scaling. As a Backend Engineer, you will benefit from comprehensive health insurance, life and family benefits, flexible vacation, visa sponsorship, and a 401(k) plan. Ideal candidates should have a good understanding of highly scalable and reliable production infrastructure, experience in designing and maintaining distributed systems, and expertise in Rust or C++.

Role

posted by company
  • 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
  • Experience in designing, implementing, and maintaining reliable and horizontally scalable distributed systems
  • Experience in operating commonly used databases such as PostgreSQL, Clickhouse, and MongoDB
  • Expert knowledge of either Rust or C++
  • Knowledge of service observability and reliability best practices
  • 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)