Verified from career page · Posted +6mo ago

Twitter

Member of Technical Staff - Sandbox Service

Twitter · Infrastructure

London

Staff Still listed after 6+ months

C++LinuxPythonRust

Last seen yesterday

Posted
+6mo ago

Posted on 18 December 2025

Workplace
Not specified

Work model not stated

Salary
£107k – £262k

Range published by Twitter

Visa sponsorship
Not specified

Visa sponsorship details unknown

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:

The Sandbox service team at SpaceXAI 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.

BASIC QUALIFICATIONS:

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 virtualisation and containerisation technologies (e.g., cgroups, KVM, gVisor, QEMU)

Solid knowledge of the networking stack

COMPENSATION AND BENEFITS:

£107,000 - £262,000 GBP

Base salary is just one part of our total rewards package at SpaceXAI, 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.

About Twitter

X's (formerly Twitter's) European postings now route through xAI's own board and are concentrated in London and Dublin. Worth noting this is the merged X/xAI entity's hiring, not a standalone Twitter career site anymore.

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