Software Engineer (Sandbox Service)

xAI; Greater London; On-site; GBP 120,000 - 170,000; Full time

Benefits offered by this job

Equity

Healthcare

Dental coverage

Cash plan

Income protection

Discounts and perks

Job summary

SpaceXAI in London is seeking a Member of Technical Staff to join the Sandbox Service team. You will help build and maintain a secure, scalable environment that lets models run code, access tools, and interact with user interfaces in real time.

You will work across the stack from cluster-level orchestration to filesystem tuning, ensuring performant, reliable environments for training and product workloads. Strong systems programming and collaboration are essential.

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.

Responsibilities

• Build and maintain the Sandbox Service infrastructure to run code, interact with tools, and manage user interfaces in real time.
• Contribute to full-stack work from cluster-level orchestration to filesystem performance tuning.
• Collaborate with model developers and product teams to ensure secure, scalable and reliable environments.

Skills

Rust

C++

Go

Python

Linux/Windows

Virtualisation & Containers

Networking

Job description

Member of Technical Staff - Sandbox Service

London, UK

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:

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.