Performance & Systems Engineer, Codex

Details

The Codex team builds state-of-the-art AI systems that can write code, reason about software, and act as intelligent agents across products such as ChatGPT and the API. The team operates across research, engineering, product, and infrastructure and owns the full lifecycle of experimentation, deployment, and iteration on novel coding capabilities.

About the Role

As a Performance & Systems Engineer on the Codex team you will be responsible for whole-system optimization across a complex, evolving stack that spans LLM inference, cloud orchestration, agentic work management, and multiple product surfaces. You will identify and land high-leverage changes across infrastructure, modeling, and product layers to make Codex agents faster and cheaper to serve. This is a high-ownership role whose work will directly improve the experience of millions of users.

This role is based in San Francisco, CA and uses a hybrid work model of 3 days in the office per week. The company offers relocation assistance to new employees.

Responsibilities

• Hunt down and address inefficiencies across the Codex system stack: agent behavior, LLM inference, container orchestration, and related components.
• 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.

Requirements / Qualifications

• Experience operating across both ML systems and cloud infrastructure.
• Ability to dive into ambiguous problems and produce clear, practical wins.
• Holistic thinking about performance that balances speed, cost, and user experience.

(Technologies and concepts mentioned in the posting: LLM inference, ML systems, cloud infrastructure, container orchestration, profiling and performance tooling, agentic work management.)

Benefits

• Base salary range listed for the role; total compensation may include equity and performance-related bonuses.
• Medical, dental, and vision insurance with employer contributions to Health Savings Accounts.
• Pre-tax accounts: Health FSA, Dependent Care FSA, commuter (parking and transit).
• 401(k) retirement plan with employer match.
• Paid parental leave (up to 24 weeks for birth parents and 20 weeks for non-birthing parents), plus paid medical and caregiver leave (up to 8 weeks).
• Paid time off: flexible PTO for exempt employees and up to 15 days annually for non-exempt employees.
• 13+ paid company holidays and additional office closures; paid sick/safe time per applicable law.
• Mental health and wellness support; employer-paid basic life and disability coverage.
• Annual learning and development stipend.
• Daily meals in offices and meal delivery credits as eligible.
• Relocation support for eligible employees.
• Additional taxable fringe benefits (charitable donation matching, wellness stipends).