Sr. Software Engineer--M365 COSMIC Team

Help build the cloud platform behind Microsoft 365’s global services.

COSMIC (Containers on Substrate-Managed Intelligent Clusters), part of the Microsoft 365 Substrate Core organization, provides a Kubernetes-based platform for running services at global scale. Our team builds the infrastructure and developer experiences that help service teams deploy and operate their workloads securely, reliably, and efficiently.

We are looking for a Senior Software Engineer to design and deliver platform capabilities, strengthen our engineering systems, and advance intelligent automation across the service lifecycle. You will work on challenges spanning distributed systems, deployment orchestration, observability, reliability, and developer productivity, using Azure and cloud-native technologies.

In this role, you will take ownership of complex features from design through production, collaborate with engineers across Microsoft, and use operational data and customer feedback to guide improvements. You will also help evolve how we build and operate the platform through AI-assisted engineering and safe, measurable operational automation.

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.

• Own end-to-end delivery of platform features and services, including technical design, implementation, testing, rollout, and production operation.

• Build reliable, scalable components for Kubernetes-based infrastructure, improving service deployment, lifecycle management, and operational workflows.

• Improve engineering quality and developer productivity through automated testing, integration validation, CI/CD systems, and reusable tooling.

• Design for security, reliability, and operability from the outset, with clear telemetry, actionable diagnostics, controlled rollouts, and recovery mechanisms.

• Develop automation that reduces repetitive work and operational risk. Where appropriate, incorporate AI-assisted or agent-based approaches with evaluation, access controls, and human oversight.

• Investigate complex production issues, identify root causes using telemetry, and deliver durable improvements to platform reliability and performance.

• Partner with product managers, engineers, and service owners to clarify requirements, make technical trade-offs, and deliver measurable outcomes.

• Participate in on-call support and incident response for the services your team owns, translating operational learnings into better software and practices.

• Mentor engineers through design discussions and code reviews, contributing to a collaborative and inclusive engineering culture.

• Bachelor's Degree in Computer Science or related technical field AND 4+ 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.

Preferred Qualifications: