Principal Software EngineerVerified as a real position

Who we’re looking for

• Bachelor's Degree in Computer Science or related technical field AND technical engineering experience with coding in languages including, but not limited to, C, C++, C#, Java, JavaScript, or Python
• OR equivalent experience.
• Experience leading architecture and delivery for large-scale distributed cloud services, high-throughput messaging platforms, email transport, service-to-service communications, or comparable mission-critical infrastructure.
• Experience driving multi-year technical initiatives across teams or organizations, including dependency alignment, architecture tradeoffs, measurable milestones, and sustained delivery through ambiguity.
• Experience with AI-assisted engineering workflows, with demonstrated judgment around Responsible AI, validation, controls, and quality ownership for AI-generated assets.
• 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.

What you’ll do

• Lead architecture, design, and implementation for complex Substrate Transport modernization work, including cloud-native platform capabilities, and integration with Exchange Online and broader M365 service dependencies.
• Partner with product managers, technical program managers, security/privacy experts, customer escalation teams, and partner engineering teams to determine requirements, validate feasibility, and translate ambiguous customer and service needs into clear technical direction and executable milestones.
• Own and broker cross-team architecture decisions across upstream and downstream dependencies, ensuring designs meet performance, scalability, resiliency, disaster-recovery, cost, security, privacy, compliance, and accessibility expectations.
• Lead by example in producing extensible, maintainable, well-tested, secure, performant code and reviewing code and test code for diagnosability, reliability, maintainability, security risks, compliance issues, and appropriate test coverage.
• Define and use the right optics, quality metrics, telemetry, dashboards, and feedback loops to guide technical decisions, measure customer value, identify risks early, and improve service health and engineering outcomes.
• Drive safe-change practices including feature flags, flighting, experimentation, deployment automation, rollback strategies, production-like validation, and secure dependency management to minimize customer impact and accelerate recovery.
• Lead live-site engineering for a globally distributed service: act as a designated responsible individual when needed, improve troubleshooting guides, reduce recurring incidents, drive retrospectives and repair items, and strengthen monitoring and operational readiness.
• Apply AI-native development practices responsibly, including appropriate controls over AI-generated requirements, designs, code, tests, and operational assets; evaluate AI tools and practices that improve engineering productivity and quality.
• Mentor and coach engineers across the team, build shared technical judgment, create clarity and energy, model Microsoft values and One Microsoft behaviors, and foster an inclusive environment where diverse perspectives improve product outcomes.
• Stay current with industry and Microsoft engineering practices, evaluate new technologies and patterns, and introduce approaches that improve quality, engineering productivity, reliability, security, and responsiveness to changing priorities.

About the position

The Substrate Transport team builds and operates the global messaging platform that underpins collaboration across Microsoft 365. We own the Exchange Online transport pipeline, processing billions of messages daily across traditional email, service-to-service communications, and emerging M365 experiences across Outlook, SharePoint, Teams, Copilot, and partner services. We are looking for a Principal Software Engineer to provide technical leadership for the modernization of Substrate Transport. This role will help re-architect a legacy, business-critical messaging platform into a cloud-native, scalable, secure, and intelligent transport system, including AI integration across the software development lifecycle. In this role, you will lead complex architecture and implementation across teams, make high-judgment technical decisions that affect service reliability and customer trust, mentor engineers, and drive measurable engineering excellence. You will operate at Principal scope by brokering hard cross-team problems, creating clarity for multi-year technical outcomes, changing the momentum of current plans toward higher customer and business impact, and creating the conditions for the team and partner teams to deliver safely at global scale.