Principal Software Engineer

Overview

The Cosmic team in M365 Core IDC builds the hyperscale cloud infrastructure that powers Microsoft 365 services, including M365 Copilot, WorkIQ, IC3, and many other mission-critical experiences. Our mission is to enable teams across M365 to deliver innovation faster with the reliability, safety, and scale required by a global cloud platform.

At the core of our work is COSMIC, Microsoft's managed container platform for cloud services. We build and operate the platform at hyperscale, enabling thousands of Microsoft 365 services to innovate, deploy, and operate faster with built-in reliability, safety, and operational excellence.

Our team drives some of Microsoft's most complex infrastructure investments across deployments, capacity management, networking, storage, security, reliability, and efficiency, solving deep engineering challenges at global scale. We have also conceived and built foundational technologies including the COSMIC Linux Platform, M365 OneBranch Deployment Platform, SDP Infrastructure, and Policy Hub, now broadly adopted across the Experiences + Devices (E+D) organization.

Our culture is built on innovation, ownership, collaboration, and continuous learning, empowering engineers to solve hard problems, drive meaningful impact, and shape the future of Microsoft 365 infrastructure.

Why Join Now

We are entering the next phase of platform transformation, reimagining how cloud services are built, deployed, and operated through AI-first and agent-driven experiences. This is a unique opportunity to:

• Shape the future of autonomous and agentic cloud platforms.
• Build AI-powered infrastructure that accelerates engineering productivity and operational efficiency.
• Push the boundaries of deployment velocity, reliability, and safety at hyperscale.
• Solve complex distributed systems challenges that directly impact Microsoft's most critical services.

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.

Responsibilities

As a Principal Software Engineer, you will:

• Drive technical strategy, architecture, and execution for hyperscale cloud platform and deployment systems.
• Lead the design and delivery of large-scale infrastructure and platform investments.
• Build secure, scalable, reliable, and maintainable distributed systems.
• Influence engineering direction through architectural leadership and technical decision-making.
• Drive operational excellence through automation, observability, and reliability engineering.
• Ensure solutions meet the highest standards of security, privacy, compliance, accessibility, and service reliability.
• Mentor engineers and foster a culture of engineering excellence across teams.
• Partner across Microsoft to deliver business impact at global scale.

Qualifications

Required/Minimum Qualifications:

• 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.

Additional or preferred qualifications

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.

Preferred Qualifications:

• Bachelor's degree in Computer Science, Engineering, or a related technical field, and 12+ years of software engineering experience.
• Solid systems thinking and architectural design expertise.
• Experience leading large-scale, geo-distributed engineering initiatives from design through delivery.
• Experience building, shipping, and operating highly available distributed systems at scale.
• Solid problem-solving, design, coding, and debugging skills.
• Experience building cloud infrastructure, platform services, or developer platforms.
• Experience leveraging AI technologies to solve platform and infrastructure challenges.
• Proven ability to mentor engineers and influence technical direction across teams.
• Experience collaborating with global stakeholders to deliver complex engineering outcomes.

#CAPIDC

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This position will be open for a minimum of 5 days, with applications accepted on an ongoing basis until the position is filled.

Microsoft is an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to age, ancestry, citizenship, color, family or medical care leave, gender identity or expression, genetic information, immigration status, marital status, medical condition, national origin, physical or mental disability, political affiliation, protected veteran or military status, race, ethnicity, religion, sex (including pregnancy), sexual orientation, or any other characteristic protected by applicable local laws, regulations and ordinances. If you need assistance with religious accommodations and/or a reasonable accommodation due to a disability during the application process, read more about requesting accommodations.