Principal Software Engineer - Substrate Store

Microsoft • Redmond, WA

1d

About The Position

We are the Store Team within Microsoft’s Substrate Storage Fabric—the core platform that fuels Microsoft 365 experiences, from the latest AI-powered Copilot innovations to Outlook and Teams, etc. Our team delivers ultra-low latency data access at massive scale, serving billions of requests per day that keep Microsoft 365 responsive and intelligent. We own and evolve the full query stack: query planning and indexing, search execution, availability, and performance optimization.
Every millisecond we shave off latency and every improvement we make to reliability directly enhances the productivity of millions of users worldwide!
We are looking for a Principal Software Engineer to help design, evolve, and modernize the core systems that power Copilot. If you’re passionate about building ultra‑low‑latency, high‑throughput services that run on a global scale, this role gives you the opportunity to shape one of Microsoft’s most strategic products. You’ll work deeply in C# and Rust to architect and optimize the performance‑critical infrastructure behind Copilot experiences used by hundreds of millions of customers. This is a chance to own foundational engineering that directly influences how AI feels—fast, responsive, and intelligent—for every user.
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.

Requirements

• 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.
• Ability to meet Microsoft, customer and/or government security screening requirements are required for this role.
• Microsoft Cloud Background Check: This position will be required to pass the Microsoft Cloud background check upon hire/transfer and every two years thereafter.

Nice To Haves

• Master's Degree in Computer Science or related technical field AND 8+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C#, Java, JavaScript, or Python.
• OR Bachelor's Degree in Computer Science or related technical field AND 12+ years technical engineering experience with coding in languages including, but not limited to, C, C++, C#, Java, JavaScript, or Python.
• OR equivalent experience.
• Proven 12+ years of experience in developing production grade applications.
• Demonstrated experience acting in the capacity of a Principal Engineer (or equivalent senior technical leadership role) for at least 2 years, with clear ownership of architecture, design decisions, and technical direction across multiple workstreams.
• On-call experience supporting production-grade, highly available systems serving millions of users, including direct responsibility for incident response, mitigation, root cause analysis, and long-term reliability improvements.
• Strong proficiency in performance profiling, debugging, and telemetry analysis.
• Expert-level proficiency in C# and/or RUST.
• Experience with large-scale production systems and incident response.
• Strong understanding of system performance, memory management, and multithreading.
• Experience working at the principal level in cross-functional engineering teams.
• Excellent problem-solving and communication skills.
• Quick learner.

Responsibilities

• Leads by example across team and mentors others to produce extensible, maintainable, well-tested, secure, and performant code used across products that adheres to design specifications.
• Designs, manages and modernizes our technology stack while keeping it within the SLAs leveraging expertise in building and optimizing latency-critical applications using C# and RUST.
• Play a pivotal role in managing, implementing and scaling systems that demand high performance and low latency.
• Reviews product code and test code to ensure it meets team standards, contains the correct test coverage, and is appropriate for the workload.
• Leads efforts to continuously improve code performance, testability, maintainability, effectiveness, and cost, while learning about and accounting for relevant trade-offs.
• Identifies best practices and coding patterns and provides deep expertise in the coding and validation strategy.
• Creates and applies metrics to drive code quality and stability, appropriate coding patterns, and best practices.
• Identifies and anticipates blockers or unknowns during the development process, escalates them, communicates how they will impact timelines, and then leads efforts to identify and implement strategies and/or opportunities to address them.
• Owns and leads efforts and discussions for the architecture of aspects of the workloads we own.
• Act as DRI and lead on-call operations, ensuring system health and rapid incident response across product lines.
• Embody our culture and values.

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level