Job Description

Sandbox / Container Runtime Engineer

Location: SF Bay Area Preferred (Remote Considered for Exceptional Candidates)
Company Stage of Funding: Series C AI Infrastructure Company
Office Type: Hybrid / Flexible Remote
Salary: $130K–$400K + Equity

We’re representing a rapidly scaling AI infrastructure company building systems that power advanced AI applications, agent evaluation platforms, and large-scale engineering workflows. Their platform supports some of the world’s leading AI organizations and operates at the intersection of distributed systems, developer infrastructure, and AI tooling.

The engineering team is focused on building high-performance runtime infrastructure that enables secure, scalable, and reproducible execution environments for developers and AI agents. This role sits within a small, highly technical platform team responsible for container runtimes, sandbox infrastructure, and developer execution environments used across the organization and external contributor ecosystem.

What You Will Do

• Build and maintain sandbox runtimes and container platform infrastructure across multiple deployment environments
• Design and improve runtime systems focused on isolation, compatibility, networking, and reliability
• Develop and optimize container runtime workflows using Docker, OCI tooling, and BuildKit
• Debug and improve multi-stage builds, multi-architecture builds, layer caching, and container performance
• Work deeply within Linux internals including namespaces, cgroups, capabilities, process supervision, and filesystem semantics
• Solve low-level networking problems involving internal DNS, nginx, port allocation, and co-located services
• Improve runtime reliability and execution consistency across distributed infrastructure environments
• Build tooling and workflows that support scalable developer and AI-agent execution environments
• Collaborate closely with platform and infrastructure engineers on runtime architecture and deployment systems
• Own runtime debugging, infrastructure reliability, and deployment ergonomics from development through production

Ideal Background

• 4–8 years of software engineering experience with strong systems or infrastructure focus
• Deep expertise with Docker, OCI tooling, and container runtime infrastructure
• Strong Linux systems knowledge including namespaces, cgroups, UID/GID mapping, capabilities, and filesystem semantics
• Experience building or substantially extending sandbox runtimes, container platforms, CI runner images, or hosted development environments
• Strong understanding of BuildKit, multi-stage builds, multi-arch builds, and advanced container debugging
• Comfortable operating close to the metal in low-level infrastructure environments
• Strong debugging instincts and ability to solve messy runtime and networking problems
• Practical, execution-oriented engineer capable of shipping reliable runtime infrastructure in fast-moving environments
• Comfortable supporting high-growth engineering organizations with external contributors and distributed workflows

Preferred

• Experience with gVisor, Firecracker, Kata Containers, microVMs, or sandbox isolation technologies
• Familiarity with browser automation runtimes, display servers, noVNC, X11, or Wayland
• Experience building hosted notebook environments, CI runners, or Codespaces-style developer environments
• Background in developer infrastructure, container platforms, or runtime engineering at scale
• Experience at infrastructure-heavy or developer-platform-focused companies
• Familiarity with networking infrastructure and runtime compatibility across heterogeneous environments

Compensation and Benefits

• Competitive salary, equity, bonuses, and relocation assistance
• Housing stipend, meal stipend, wellness benefits, and premium healthcare coverage
• Opportunity to build foundational runtime infrastructure powering large-scale AI workflows
• High-autonomy engineering culture with strong technical ownership
• Exposure to deeply technical systems problems involving containerization, runtime isolation, and developer infrastructure
• Fast-paced environment focused on shipping practical systems and solving infrastructure bottlenecks at scale