Software Engineer, API Frontiers

Job summary

Responsibilities

We are looking for a backend software engineer to build and operate the services behind the Responses API. You will shape API behavior, bring new capabilities from research into production, and make long-running agent workflows dependable and fast.

• Design, build, and operate APIs and backend services that bring frontier model capabilities to developers.
• Partner with Research, Safety, Codex, and API teams to define API behavior and deliver safe, staged launches.
• Build API capabilities for agent workflows, including task delegation, context sharing, and parallel execution.
• Strengthen long-running request reliability across timeouts, cancellation, streaming, and background execution.
• Improve request-processing performance and tail latency through profiling, efficient systems code, and persistent connections.

What they're looking for

• 5+ years of experience building and operating backend services or developer-facing APIs in production.
• Strong software engineering fundamentals, with practical knowledge of distributed systems, concurrency, and asynchronous execution.
• Ability to diagnose production failures and performance bottlenecks using observability data and profiling.
• Product judgment and developer empathy, with a track record of translating complex capabilities into clear, dependable APIs.
• Experience taking ownership of ambiguous technical problems, from defining an approach through shipping and improving the result.

Tech stack

• Rust