Performance & Systems Engineer, Codex

As a Performance & Systems Engineer on the Codex team, you will be responsible for whole-system optimization across a complex, evolving stack. Codex spans LLM inference, cloud orchestration, agentic work management, and multiple product surfaces. Your job will be to identify and land high-leverage changes—across infrastructure, modeling, and product layers—that make Codex agents significantly faster and cheaper to serve. We’re looking for generalists who thrive in ambiguity and love chasing performance bottlenecks to ground. This is a high-ownership role where your work will directly improve the experience of millions of users.

Responsibilities

Hunt down and address inefficiencies across the Codex system stack, from agent behavior to LLM inference to container orchestration, and beyond; Build tooling to measure, profile, and optimize system performance at scale; Collaborate with researchers and engineers to land high-ROI changes that improve latency and cost; Identify and land high-leverage changes across infrastructure, modeling, and product layers that make Codex agents significantly faster and cheaper to serve

Requirements

Experience operating across both ML systems and cloud infrastructure; Enjoy diving into messy, ambiguous problems and emerging with clear wins; Think holistically about performance, balancing speed, cost, and user experience; Generalist who thrives in ambiguity; Love chasing performance bottlenecks to ground

Benefits

Relocation assistance to new employees