Principal Software Engineer, Full Stack — Codex

About the Role We’re hiring a Principal Software Engineer to help define and build the next generation of AI-powered software development workflows. “Full stack” in this role extends well beyond traditional frontend and backend development. You will set technical direction and lead major product initiatives spanning user interfaces, developer tooling, workflow orchestration, agent and prompt design, backend systems, and cloud infrastructure. This is a highly product-oriented technical leadership role. You will identify the highest-leverage opportunities across the software development lifecycle, turn ambiguous user and technical problems into durable product and system strategies, and lead execution across multiple engineers and partner teams. Your work will shape both the architecture of Codex and how developers around the world design, write, review, test, and maintain software. You will operate as a senior individual contributor: remaining deeply involved in design and implementation while raising the technical judgment, execution quality, and ambition of the broader team. In this role, you will - Set the technical and product direction for significant areas of Codex, translating an evolving product vision into scalable architectures and an actionable engineering strategy. - Lead complex, multi-quarter initiatives spanning client applications, backend services, agent systems, cloud infrastructure, and developer tooling. - Design AI-powered workflows that generalize across languages, codebases, development environments, and organizations while remaining intuitive, reliable, and safe. - Make high-consequence architectural decisions under ambiguity, balancing rapid product learning with long-term system quality and adaptability. - Identify opportunities that cut across existing team or product boundaries, align stakeholders around a direction, and drive the work from exploration through launch and iteration. - Partner closely with product, design, research, infrastructure, security, and go-to-market teams to turn emerging model capabilities and developer needs into coherent product experiences. - Work directly with developers, open-source maintainers, startups, and large enterprises to uncover unmet needs and distinguish foundational opportunities from incremental improvements. - Establish patterns and standards for reliability, observability, performance, experimentation, and evaluation across AI-powered developer workflows. - Serve as a technical multiplier by reviewing critical designs, mentoring engineers, improving engineering practices, and helping the team navigate its hardest product and technical decisions. - Contribute directly to implementation, particularly where the problem is novel, technically demanding, or requires connecting multiple layers of the product. You might thrive in this role if you - Have led the design and delivery of technically complex, user-facing systems with impact extending beyond a single feature or team. - Combine deep software-engineering expertise with exceptional product judgment and can move fluently across product interfaces, distributed systems, infrastructure, and developer tooling. - Have a track record of creating clarity in ambiguous problem spaces, setting a compelling technical direction, and bringing multiple teams or disciplines along with you. - Remain hands-on while increasing the effectiveness of other engineers through architecture, mentorship, decision-making, and technical leadership. - Understand modern software-development workflows deeply and can recognize where AI agents require fundamentally new interaction and system designs. - Have experience building or operating AI-powered products and understand the challenges created by nonde