Backend Engineer - API

xAI•Palo Alto, CA

18h•$180,000 - $440,000

About The Position

xAI's mission is to create AI systems that can accurately understand the universe and aid humanity in its pursuit of knowledge. The team is small, highly motivated, and focused on engineering excellence, operating with a flat organizational structure. All employees are expected to be hands-on, contribute directly to the company’s mission, show initiative, and consistently deliver excellence. Strong work ethic, prioritization, and communication skills are essential. As a Backend Engineer, the ideal candidate has a good understanding of how highly scalable and reliable production infrastructure is built. Most of the backend infrastructure is written in Rust, so familiarity with a compiled language such as C++, Rust, or Go is highly beneficial.

Requirements

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

Nice To Haves

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)

Responsibilities

Build the xAI 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