Software Engineer, Sandboxing

About This Role

This engineering role focuses on building and operating the sandboxing infrastructure that runs untrusted, model-generated code and agent workloads at scale. The work involves improving sandbox performance, strengthening isolation, and partnering with research, product, and security teams to ensure safety and speed.

Responsibilities

• Design, build, and operate the sandboxing infrastructure that runs untrusted, model-generated code and agent workloads at scale
• Improve sandbox startup time, density, and throughput, including snapshot and restore, checkpointing, and warm pools
• Strengthen isolation across compute, filesystem, and network, including egress controls and per-session credential handling
• Investigate and fix performance, reliability, and security issues at the kernel, hypervisor, and container runtime level
• Build the monitoring, tracing, and debugging tools that show where time and resources go inside a sandbox
• Work with researchers to support reinforcement learning environments and evaluations that need fast, reproducible, isolated execution
• Work with product and platform engineers to expose sandboxes as a dependable, well-designed capability for Claude products and customers
• Partner with security teams to threat-model the platform and to test, harden, and respond to escape and abuse scenarios
• Work with cloud providers on the hardware and platform features that our workloads depend on
• Share knowledge on systems programming and Linux internals, and help set technical standards for the team

Requirements

• Software engineering experience in Linux systems programming, kernel development, or another low-level area
• Strong programming skills in at least one systems language such as Rust, C, C++, or Go
• Working knowledge of virtualization or container isolation technologies such as KVM, QEMU, Firecracker, gVisor, or runc
• Understanding of Linux resource management, including namespaces, cgroups, scheduling, and memory management
• Experience profiling and debugging performance issues at the system level
• Ability to work in unfamiliar codebases and technical areas, and to ship practical solutions with measurable results
• Strong communication skills and a commitment to building safe, reliable systems

Nice to have:

• Experience building or operating a multi-tenant sandbox, serverless, or code execution platform
• Experience with microVMs, user-space kernels, or lightweight virtualization, including snapshot and restore
• Experience with OS-level security hardening, including seccomp, LSMs, and threat modeling of untrusted code
• Experience with eBPF and kernel tracing tools