AI Infrastructure Engineer, Sandbox Platform

London, UK

Join the team shaping the future of AI at Scale.

As a Software Engineer on the AI Infrastructure team, you'll help build and evolve our agent sandboxing platform — the secure, high-performance code execution layer powering our agentic workflows, deployed across both internal and customer-managed environments. This is a role for someone who cares as much about the experience of the engineers and researchers using this system as they do about the kernel internals underneath it.

You'll combine deep systems expertise (isolation, virtualisation, performance) with an obsession for developer experience: clean APIs, clear error messages, good docs, and a client library that feels well-crafted. You'll partner closely with internal teams to understand how they use the platform, debug their issues, and shape a roadmap that balances immediate needs with long-term architecture.

• Design and build the sandboxing platform, client library, and API surface for secure code execution across containerized and virtualized environments
• Ensure strong isolation, security, and reproducibility of execution across user sessions and workloads
• Optimise for cold-start latency, memory footprint, and resource utilisation at scale
• Drive down error rates through systematic debugging, monitoring, and proactive fixes
• Partner closely with internal teams using the platform to understand their needs, debug issues, and build tooling that serves their use cases
• Respond to incidents and production issues with urgency, conducting root cause analysis and implementing preventive fixes
• Help develop and maintain a product roadmap for sandboxing, balancing immediate needs against long-term architectural investment
• Lead architecture reviews and own projects end-to-end, from design through deployment, in fast-paced cross-functional settings

• 4+ years of experience building high-performance systems software, with meaningful time spent maintaining libraries, SDKs, or developer-facing APIs
• Deep understanding of Linux internals: process isolation, memory management, cgroups, name spaces, etc.
• Experience with containerisation and virtualisation technologies (e.g., Docker, Firecracker, gVisor, QEMU, Kata Containers)
• Proficiency in a systems programming language such as Go, Rust, or C/C++
• A track record of obsessing over developer experience — API design, error propagation, documentation, and the small details that make a library feel well-crafted
• Comfort working across infrastructure layers, from kernel modules to orchestration frameworks (e.g., Kubernetes)
• Strong debugging skills and the ability to navigate performance/security tradeoffs in production systems
• Comfort with ambiguity, and the ability to context-switch between reactive incident work and proactive product development

• Experience as a founder or early engineer at an infrastructure-focused startup, owning a product end-to-end
• Familiarity with LLM agents and agent frameworks (e.g., Open Hands, Agent2
  
  Agent, MCP)
• Experience running secure workloads in multi-tenant or untrusted environments (e.g., FaaS, CI sandboxes, remote notebooks)
• Exposure to snapshotting and restore techniques (e.g., CRIU, VM snapshots, overlays)
• Open-source contributions to systems or developer-tools projects
• History of on-call/incident response for production systems

PLEASE NOTE:Our policy requires a 90-day waiting period before reconsidering candidates for the same role. This allows us to ensure a fair and thorough evaluation of all applicants.

About Us:

At Scale, our mission is to develop reliable AI systems for the world's most important decisions. Our products provide the high-quality data and full-stack technologies that power the world's leading models, and help enterprises and…