# Backend Engineer - API

**Company:** [xAI](https://hotfix.jobs/companies/xai)
**Location:** London, United Kingdom
**Role:** Backend Engineering
**Salary:** £107k – £262k/yr
**Skills:** Rust, C++, Distributed Systems, Postgres, ClickHouse, MongoDB, Llm Inference, Sglang, TensorRT, vLLM, Agent Sdks, Docker, Kubernetes, gRPC
**Posted:** 2026-08-13

> Build and operate the high-throughput API and model-serving infrastructure powering SpaceXAI’s production inference systems. The role requires expert Rust or C++ knowledge, distributed-systems experience, and strong reliability and observability practices.

## Job Description

## Responsibilities
- Build the SpaceXAI API that serves models to developers worldwide.
- Own the end-to-end system for high-throughput inference, handling billions of tokens per minute with low latency and high availability.
- Develop and maintain model-serving infrastructure, request routing, SDKs, rate limiting, observability, and efficient scaling.

## Requirements
- Expert knowledge of Rust or C++.
- Experience designing, implementing, and maintaining reliable, horizontally scalable distributed systems.
- Knowledge of service observability and reliability best practices.
- Experience operating databases such as PostgreSQL, ClickHouse, and MongoDB.

## Nice-to-haves
- Experience with LLM inference engines and serving frameworks such as SGLang, TensorRT, or vLLM.
- Experience designing or building with agent SDKs and agent orchestration frameworks.
- Experience with Docker, Kubernetes, and containerized applications.
- Expert knowledge of gRPC, including unary, response streaming, bidirectional streaming, and REST mapping.

## Compensation and Benefits
- Base salary: £107,000–£262,000 GBP.
- Equity.
- Comprehensive healthcare and dental coverage.
- Cash plan.
- Income protection.
- Life insurance.
- Other discounts and perks.

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