Software Engineer, Compute and Isolation at Baseten · LumiJobs
$165k–$330k
H1B: no
Baseten Software Engineer on the Agent Infra team owning the microVM lifecycle for agent sandboxes. Responsible for building and tuning custom guest kernels and managing host CPU and memory configurations for sandbox performance and isolation.
Responsibilities
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. General-purpose virtualization was not built for that workload.
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. In September 2026, Baseten acquired Blaxel, whose microVM sandboxes are the foundation for Baseten Sandboxes.
We are building a cloud, not just using one. That means designing for many tenants from day one and thinking through what each decision means all the way down to the datacenter. The team is small and ownership is big: we ship in weeks and months, not multi-year programs.
If you've worked deep in KVM and Firecracker, Cloud Hypervisor, or QEMU and want to build the computers AI agents run on, we'd love to talk.
EXAMPLE INITIATIVES
Blaxel is joining Baseten to build the future of agentic infrastructure
Securing the open frontier with NVIDIA OpenShell and Blaxel sandboxes
Baseten Sandboxes documentation
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
Qualification
Hands-on experience with KVMDeep understanding of Linux internalsContributions to KVMExperience with XenExperience with VM snapshot and restoreExperience building a sandbox
Required
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
Preferred
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
