Sandboxing Engineer – AI Model Execution & Security

Mosaic.tech; San Francisco (CA); On-site; USD 300,000 - 450,000; Full time

Benefits offered by this job

Health, dental, vision benefits

Unlimited PTO

Parental leave

Relocation support

Job summary

Thinking Machines is hiring a software engineer to design, build, and operate a sandboxing platform that runs model-generated code and tool calls at scale in San Francisco. You will contribute to secure isolation, scheduling, and observability of thousands of concurrent executions.

The role emphasizes end-to-end ownership, collaboration with researchers and product teams, and delivering fast, reliable, and secure infrastructure that enables researchers to train and deploy agents and tools with

Qualifications

• Bachelor's degree or equivalent in CS, Engineering, or related field.
• Proficiency in Python or Rust for backend development.
• Experience building/operating isolation or virtualization tech.
• Strong knowledge of Linux internals: namespaces, cgroups, seccomp, capabilities, networking.
• Ability to own projects end-to-end in a collaborative environment.
• Thrive in a highly collaborative environment with cross-functional partners.

Responsibilities

• Design, build, and operate sandboxed execution environments for running untrusted, model-generated code and tool calls at scale.
• Improve isolation boundaries using containers, microVMs, or gVisor-style kernels.
• Build scheduling, resource-management, and lifecycle systems for sandboxes under heavy concurrent load.
• Partner with researchers and Tinker's product team to expose sandboxing primitives that are simple to use and hard to misuse.
• Instrument sandboxes for observability and abuse detection, and respond to novel escape or exploitation attempts.
• Own reliability and performance end-to-end from API design down to the virtualization layer.

Skills

Python

Rust

Linux internals

Distributed systems

End-to-end ownership

Education

Bachelor's degree in CS/Engineering

Tools

Kubernetes

Firecracker

Cloud Hypervisor

gVisor

Kata Containers

Job description

Thinking Machines is hiring a software engineer to design, build, and operate a sandboxing platform that runs model-generated code and tool calls at scale in San Francisco. You will contribute to secure isolation, scheduling, and observability of thousands of concurrent executions.

The role emphasizes end-to-end ownership, collaboration with researchers and product teams, and delivering fast, reliable, and secure infrastructure that enables researchers to train and deploy agents and tools with