Software Engineer II & Senior Software Engineer

Security represents the most critical priorities for our customers in a world awash in digital threats, regulatory scrutiny, and estate complexity. Microsoft Security aspires to make the world a safer place for all. We want to reshape security and empower every user, customer, and developer with a security cloud that protects them with end to end, simplified solutions. The Microsoft Security organization accelerates Microsoft’s mission and bold ambitions to ensure that our company and industry is securing digital technology platforms, devices, and clouds in our customers’ heterogeneous environments, as well as ensuring the security of our own internal estate. Our culture is centered on embracing a growth mindset, a theme of inspiring excellence, and encouraging teams and leaders to bring their best each day. In doing so, we create life-changing innovations that impact billions of lives around the world.

Attacks begin on the endpoint—it’s where an intruder first lands, runs malware, and moves laterally across a network. It’s also where their activity can be observed most clearly in real time.

The Microsoft Defender for Endpoint (MDE) client for macOS runs directly on our enterprise customers’ Macs, continuously monitoring processes, files, and system events. It blocks threats on the device and transforms what it observes into high-fidelity signals that power investigation and response across Microsoft Security. Operating across diverse macOS versions and large enterprise fleets—without negatively impacting device performance—is a complex systems challenge.

The agent runs close to the operating system using system extensions and the Endpoint Security Framework, integrating deeply with the macOS security model to extend and enhance the protections our customers already rely on.

We are looking for a Software Engineer II and a Senior Software Engineer who are passionate about building fast, reliable, native systems software and want to shape a macOS product that protects enterprise environments against real-world attacks. Our team's engineers have the opportunity to influence technical direction, own the architecture of major features and subsystems, and elevate the engineers around them.

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.

We transform high-volume process, file, and security events across macOS into a fast, accurate, and durable account of activity—forming a foundation for Microsoft Security. In this role, you will:

• Build and improve detection, OS event monitoring, telemetry, and reporting in the on-device agent
• Develop native components that detect and respond to real-world endpoint threats
• Design, deliver, and maintain components with a focus on reliability, performance, and operational health
• Help ensure the agent remains efficient, safe, and aligned with the macOS security model
• Contribute to performance, concurrency, and compatibility across macOS versions
• Produce high-quality telemetry that supports investigation, analytics, and security insights
• Investigate and resolve issues such as crashes, performance regressions, and compatibility challenges
• Apply secure coding practices and validate assumptions to build resilient systems
• Collaborate with engineers and partner teams to deliver integrated security solutions
• Contribute to design discussions, code reviews, and shared engineering practices
• Embody our culture and values.