Member of Technical Staff - Sandbox Service London, UK

xAI’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 engineers are expected to have strong communication skills. They should be able to concisely and accurately share knowledge with their teammates.

About the team: The Sandbox service team at xAI builds and maintains a secure, scalable system that gives our models safe, controlled access to computational environments. This infrastructure powers critical workloads across training and product, enabling models to run code, build software, interact with tools, and even control applications with user interfaces. We provision containers and virtual machines on large‑scale clusters, granting models interactive control over these remote environments. Our work spans the full stack: from orchestrating massive jobs and resource scheduling at the cluster level, to fine‑tuning filesystem performance on nodes. The Sandbox service enables Grok to safely run and test code in real‑time for user queries, and supports reinforcement learning in training, where models interactively explore tools ranging from compilers to productivity apps.

About the role: Expect deeply technical work in a fast‑moving environment. We prioritize speed and rapid iteration without compromising on reliability or performance. Ideal candidates have strong backgrounds in at least the following:

• Expert knowledge of Rust, C++ or Go
• Familiarity with Python
• Deep experience with either Linux or Windows systems (familiarity with both is a strong plus)
• Experience with virtualization and containerization technologies (e.g., cgroups, KVM, gVisor, QEMU)
• Solid knowledge of the networking stack

After submitting your application, the team reviews your statement of exceptional work and CV. If your application passes this stage, you will be invited to a 15 minute interview (“phone interview”) during which a member of our team will ask some basic technical questions. If you clear the initial phone interview, you will enter the main process, which consists of at least two technical interviews: Coding interview in Rust or C++.

Base salary is just one part of our total rewards package at xAI, which also includes equity, comprehensive medical, vision, and dental coverage, access to a 401(k) retirement plan, short & long‑term disability insurance, life insurance, and various other discounts and perks.

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