Backend engineer for APIs

SpaceXSI is building Super Intelligence to help humanity understand the universe. Our teams are building the full Super Intelligence stack: from our Colossus supercomputers, to Grok models, to our suite of applications, including Grok Bot, Grok Build, Grok Imagine, Grok Voice, and X. We're creating a powerful flywheel where more compute trains better models, better models power more useful products, and what we learn from people using those products shapes what we build next.

• 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

• 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
• Будет плюсом: 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)

• £107,000 - £262,000 GBP
• Base salary is just one part of our total rewards package at SpaceXSI, which also includes equity, comprehensive healthcare and dental coverage, cash plan, income protection, life insurance, and various other discounts and perks.