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Backend Engineer

xAI· London, UK· £107,000–£262,000/yrEquityLicensed sponsor
Posted 25 Nov 2025 · Added 20 Jun 2026, 20:00
Xai3.2 (5)
AI summary

You'll build production backend infrastructure for xAI's API using primarily Rust, working on highly scalable distributed systems that power AI technology aimed at understanding the universe. Required expertise includes Rust or C++, distributed systems design, database management (PostgreSQL, Clickhouse, MongoDB), and service reliability practices. Preferred skills include Python, Kubernetes, gRPC, and LLM API experience.

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SpaceXAI’s mission is to create AI systems that can accurately understand the universe and aid humanity in its pursuit of knowledge. Our team is small, highly motivated, and focused on engineering excellence. This organization is for individuals who appreciate challenging themselves and thrive on curiosity. We operate with a flat organizational structure. All employees are expected to be hands-on and to contribute directly to the company’s mission. Leadership is given to those who show initiative and consistently deliver excellence. Work ethic and strong prioritization skills are important. All employees are expected to have strong communication skills. They should be able to concisely and accurately share knowledge with their teammates.

ABOUT THE ROLE:

In this role you will work on SpaceXAI's production systems that power the API. The actual team matching will happen at the offer stage.

As an ideal candidate you have a good understanding of how highly scalable and reliable production infrastructure is built. You strive for perfection and listen carefully to your users in order to solve any pain points they might experience. Most of our backend infrastructure is written in Rust. So familiarity with a compiled language such as C++, Rust, or Go is highly beneficial.

BASIC QUALIFICATIONS:

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.

PREFERRED SKILLS AND EXPERIENCE

Knowledge of Python,

Experience with Docker, Kubernetes, and containerized applications,

Expert knowledge of gRPC (unary, response streaming, bi-directional streaming, REST mapping),

Hands-on experience with LLM APIs, embeddings, or RAG patterns,

Track record of delivering user-facing software at scale.

COMPENSATION AND BENEFITS:

£107,000 - £262,000 GBP

Base salary is just one part of our total rewards package at SpaceXAI's, which also includes equity, comprehensive healthcare and dental coverage, cash plan, income protection, life insurance, and various other discounts and perks.

SpaceXAI is an equal opportunity employer. For details on data processing, view our Recruitment Privacy Notice.