Senior Software Engineer, Windows Sandboxes

Recruiting From Scratch; San Francisco (CA); On-site; USD 215,000 - 285,000; Full time

Benefits offered by this job

Equity

Job summary

Recruiting From Scratch is seeking a Senior Software Engineer to own the Windows Sandboxes stack. You will engineer the Windows guest stack on KVM/QEMU, develop virtio drivers and guest agents, and optimize boot and latency for instant-start sandboxes.

You will also build snapshot/fork features, APIs for AI agent interaction, and scalable image/update pipelines. You will work with a small, senior team on Linux virtualization, Windows internals, and AI agent infrastructure, shaping a serverless

Qualifications

• 5 years of professional systems, infrastructure, virtualization, or platform engineering experience.
• Hands-on production experience running Windows guests on Linux hypervisors such as KVM/QEMU.
• Strong understanding of Windows internals, including boot processes, services, session management, and the registry.

Responsibilities

• Build and productionize the Windows guest stack on KVM/QEMU infrastructure.
• Develop and integrate virtio drivers, guest agents, image pipelines, and unattended provisioning systems.
• Optimize Windows boot, session initialization, and login latency for instant-start sandboxes.
• Build snapshot, restore, pause, and fork capabilities for Windows VMs.
• Develop control-plane APIs for programmatic interaction with Windows environments.
• Build infrastructure for input injection, display streaming, file transfer, and lifecycle management.
• Automate Windows image creation, patching, Sysprep, and golden image management.
• Build scalable image update and deployment infrastructure across production fleet.
• Instrument Windows hosts to improve VM density, reliability, and cost per sandbox.
• Debug issues across KVM/QEMU, Windows kernel, services, drivers, and guest environments.

Skills

Go

Rust

C

C#

Tools

KVM/QEMU

virtio drivers

Job description

Senior Software Engineer, Windows Sandboxes

Location: San Francisco, CA

Company Stage of Funding: Series A

Office Type: In Person

Salary: $215,000-$285,000 Equity

We're representing a rapidly growing infrastructure company building the compute layer for AI agents. Its platform provides secure, isolated, instantly available sandboxes where AI agents can execute code, interact with computers, and run training workloads.

Following its Series A, the company has already grown 10x and is now expanding its infrastructure to make Windows environments available as an on-demand, serverless primitive. The team is solving difficult systems problems spanning Linux virtualization and Windows internals—making Windows VMs boot quickly, snapshot and restore efficiently, fork on demand, and expose desktop applications directly to AI agents through APIs.

This is a deeply technical systems engineering role for someone comfortable debugging across hypervisors, operating systems, drivers, and production infrastructure.

What You Will Do

• Build and productionize the Windows guest stack running on KVM/QEMU infrastructure.
• Develop and integrate virtio drivers, guest agents, image pipelines, and unattended provisioning systems.
• Optimize Windows boot, session initialization, and login latency to create an instant-start sandbox experience.
• Build snapshot, restore, pause, and fork capabilities for Windows virtual machines.
• Develop control-plane APIs that allow AI agents to interact programmatically with Windows environments.
• Build infrastructure for input injection, display streaming, file transfer, and application and process lifecycle management.
• Automate Windows image creation, software installation, patching, Sysprep, and golden image management.
• Build scalable image update and deployment infrastructure across a production fleet.
• Instrument Windows hosts and improve VM density, infrastructure utilization, reliability, and cost per sandbox.
• Debug difficult systems problems spanning the KVM/QEMU hypervisor, Windows kernel, services, drivers, and guest environments.
• Build observability and automation that make Windows infrastructure reliable at production scale.
• Own systems from architecture and implementation through deployment, operations, incident response, and ongoing improvement.

Ideal Background

• 5 years of professional systems, infrastructure, virtualization, or platform engineering experience.
• Hands-on production experience running Windows guests on Linux hypervisors such as KVM/QEMU.
• Alternatively, deep Windows virtualization experience with strong knowledge transferable to KVM/QEMU and virtio environments.
• Strong understanding of Windows internals, including boot processes, services, session management, and the registry.
• Experience automating Windows environments using PowerShell, WinRM, unattended provisioning, or similar tooling.
• Strong systems programming skills with Go, Rust, C, C , or C# for systems-level development.
• Experience debugging issues across virtualization and operating system boundaries.
• Strong understanding of production infrastructure, reliability, observability, and performance optimization.
• Comfortable working close to operating systems, drivers, networking, and virtualization layers.
• High ownership mindset with experience operating and supporting the production systems you build.
• Comfortable solving ambiguous, low-level engineering problems within a small and fast-moving team.

Preferred

• Experience with remote display protocols or streaming infrastructure such as RDP, SPICE, or WebRTC.
• Windows driver development experience.
• Experience developing guest agents or other software that interfaces directly with virtualization platforms.
• Background building VDI, Cloud PC, desktop virtualization, or remote workstation infrastructure.
• Experience with desktop automation or large-scale UI testing infrastructure.
• Experience building infrastructure for computer-use AI agents.
• Familiarity with Packer or other image-as-code tooling for Windows environments.
• Experience optimizing Windows VM startup, snapshotting, image management, or host density.
• Background at a virtualization, cloud infrastructure, serverless compute, VDI, or hyperscaler infrastructure organization.
• Experience building control planes or APIs for programmatic interaction with virtual machines.

Compensation and Benefits

• Competitive base salary plus equity.
• Full-time position reporting to the Engineering Lead for Windows Sandboxes.
• Location options in San Francisco or Croatia.
• Opportunity to work on unusual systems challenges at the intersection of Linux virtualization, Windows internals, and AI agent infrastructure.
• Join shortly after the company's Series A during a period of rapid growth, with the platform already having grown approximately 10x.
• Work within a small, senior engineering team where individual contributors have substantial technical and production ownership.
• Opportunity to help create a serverless Windows platform where AI agents can instantly launch, control, snapshot, and fork real desktop environments.
• Salary Range: $215,000-$285,000 base.