Software Engineer, Compute and Isolation

About Baseten

Baseten powers mission-critical inference for the world's most dynamic AI companies, like Cursor, Notion, OpenEvidence, Abridge, Clay, Gamma, and Writer. By uniting applied AI research, flexible infrastructure, and seamless developer tooling, we enable companies operating at the frontier of AI to bring cutting-edge models into production.

The Role

Every agent on Baseten Sandboxes gets its own microVM, where it writes and runs code, calls tools, and keeps state across long tasks. Agents pause and resume constantly, so the machine underneath has to start, stop, snapshot, fork, and resume fast, and keep every tenant isolated while it does.

The Agent Infra team builds that layer. Sandboxes run in microVMs with custom Linux kernels on bare-metal servers we operate. You'll own how sandboxes start, stop, snapshot, fork, and resume, and how they perform on each host's CPU and memory, down to the hardware. You'll also own the guest and host side of each sandbox: its identity, how it attaches to different storage classes for performance or capabilities, and the virtual devices that connect it securely to the network.

Responsibilities

• Own the microVM lifecycle for agent sandboxes: start, stop, suspend, resume, snapshot, and fork
• Build and tune the custom guest kernels sandboxes run on
• Tune host CPU and memory configuration so sandboxes run fast and safely on each type of hardware we operate
• Manage host-level resources and sandbox density on each machine
• Own startup and resume performance end to end, from VM boot or snapshot restore to the first command
• Own the guest and host side of each sandbox: its identity, how it attaches to storage, and the virtual devices that connect it to the network
• Design isolation for multi-tenant workloads where the hypervisor is the security boundary
• Debug virtualization and isolation issues at scale, from userspace through the kernel to the hardware
• Contribute architecture decisions and code back to the open-source projects we build on

Requirements

• Hands-on experience with KVM, plus Firecracker, Cloud Hypervisor, or QEMU
• Deep understanding of Linux internals: namespaces, cgroups, memory management, and the boot path
• Experience building cloud infrastructure as the provider (multi-tenant compute that customers run on), not only running workloads on a cloud provider
• Experience building multi-tenant infrastructure where isolation is a security boundary
• Strong systems programming background in Rust and/or Go; C/C++ also welcome
• Experience debugging performance and correctness problems across userspace and kernel boundaries
• You move fast and like owning a problem end to end on a small team

Nice to Have

• Contributions to KVM, Firecracker, Cloud Hypervisor, QEMU, rust-vmm, or the Linux kernel
• Experience with Xen
• Working knowledge of container runtimes and sandboxing (containerd, runc, gVisor, Kata Containers)
• Experience with VM snapshot and restore, fast VM resume, or building and tuning custom Linux kernels
• Experience running virtualization on bare metal and tuning for specific CPU and memory architectures
• Experience building a sandbox, serverless, or function runtime product
• Familiarity with Linux performance tooling such as eBPF, perf, and ftrace