Principal Software Engineer

We are looking for a Principal Software Engineer to join our team! We are the team that defines how users interact with Copilot in Microsoft 365. Our charter is to build foundational UX systems that make Copilot feel intelligent, responsive, and deeply integrated into the flow of work. We own the core interaction surfaces and frameworks that power Copilot's presence across endpoints -- Teams, Outlook, M365.com, and Office apps. This includes the Shell, Navigation, Input, Sessions, Feedback and Settings, as well as proactive and assistive UX patterns.

We operate as a vertical and horizontal team, partnering across product, design, and engineering to deliver consistent, high-quality experiences at scale. Our work is grounded in telemetry, user research, and a relentless focus on performance, accessibility, and craft.

We're looking for a full-stack engineer to help shape the future of AI-powered productivity experiences in Microsoft 365. You'll join a team building intuitive, performant, and accessible user interfaces that connect millions of users with the power of Copilot.

Microsoft's mission is to empower every person and every organization on the planet to achieve more. As employees we come together with a growth mindset, innovate to empower others, and collaborate to realize our shared goals. Each day we build on our values of respect, integrity, and accountability to create a culture of inclusion where everyone can thrive at work and beyond.

What You'll Do

• Define unified, scalable, modular, and maintainable front-end architectures using client/service stacks such as React, TypeScript, Node.js, while integrating design frameworks such as component libraries to ensure globally consistent UX.
• Drive performance, scalability, memory efficiency, and usability initiatives across multiple surfaces, collaborating closely with partner teams.
• Drive initiatives aimed at increasing customer reach, engagement, and satisfaction.
• Lead technical design discussions and mentor engineers across the organization.
• Develop and drive the cross-org adoption of shared infrastructure, component libraries, and best practices. Establish governance & standards with contribution guidelines and continuous integration (CI).
• Collaborate with PM, design, and engineering leaders to innovate, prototype, and advocate for novel ideas.
• Enable rapid design updates through tooling and abstraction layers.

What We're Looking For

• 6+years of experience building production-grade web applications.
• Expertise in JavaScript, React, Node.js, and modern front-end and service tooling.
• Strong understanding of front-end architecture, performance optimization, memory management, cross-browser compatibility.
• Experience working in large-scale, distributed teams.
• Passion for user experience, craftsmanship, and clean code.

• Bachelor's Degree in Computer Science or related technical field AND 6+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C#, Java, JavaScript, or Python
  • OR equivalent experience.

Other Requirements:

• Ability to meet Microsoft, customer and/or government security screening requirements are required for this role. These requirements include but are not limited to the following specialized security screenings:
• Microsoft Cloud Background Check: This position will be required to pass the Microsoft Cloud background check upon hire/transfer and every two years thereafter.