Software Engineer, Codex Core Agents

What You’ll Do

• Design and build execution environments for AI agents, including sandboxing, isolation, and reproducibility.
• Develop systems for agent orchestration across multi-step, tool-using workflows.
• Build infrastructure for running, testing, and debugging code generated by models.
• Create state and memory systems that allow agents to persist context across long-running tasks.
• Optimize tokens, latency, reliability, and cost across Codex’s production fleet.
• Support model rollouts, capacity planning, and the core tradeoffs between quality, speed, and economics to manage a fleet of frontier agents at scale.
• Build shared platform capabilities that unblock product teams, partner teams, and open source Codex.

What You Might Be a Good Fit If You

• Have strong experience in distributed systems or infrastructure engineering.
• Have built systems involving containers, sandboxing, or virtualization.
• Are comfortable working across backend systems, APIs, and developer tooling.
• Care deeply about system reliability, performance, and security.
• Enjoy working on ambiguous, zero-to-one problems.
• Want to help build the systems that turn model capability into a dependable software engineering agent.

Bonus Points

• Experience with code execution platforms, CI/CD systems, or build systems.
• Familiarity with LLMs, agents, or tool-use frameworks.
• Background in security engineering or isolation systems.
• Experience building developer platforms, IDE tooling, or open source infrastructure.