Matthew Kotsenas
Principal Software Engineer, Microsoft Defender For Endpoint
Seattle, Washington, United States
Summary
🤩
Rockstar🎓
Top SchoolMatthew Kotsenas is a Principal Software Engineer at Microsoft with 14 years of experience building developer-focused infrastructure and secure, scalable web services, currently shaping Microsoft Defender for Endpoint. He has a strong background improving developer productivity across build, test, and CI/CD systems for Edge and Chromium, blending hands-on backend engineering with program and product management. An active open-source contributor, Matthew has improved core .NET runtime async process APIs and hardened test suites in libraries like SharpCompress, and enhanced cross-platform tooling such as the popular "thefuck" shell fixer for Windows PowerShell. Based in Seattle and trained in software engineering at RIT, he pairs deep technical stewardship with a practical focus on reliability, efficiency, and developer experience—plus an unusual personal discipline: ultra and trail running informs his approach to sustained focus and problem solving.
14 years of coding experience
11 years of employment as a software developer
Bachelor’s Degree, Computer Software Engineering, Bachelor’s Degree, Computer Software Engineering at Rochester Institute of Technology
English
Github Skills (25)
asynchronous10
unit-testing10
python10
scripting10
async10
testing10
net10
dotnet10
netframework10
asp-net10
script10
dotnet-core10
sharpcompress10
sh10
compression10
Programming languages (14)
Github contributions (5)
dotnet/runtime
Jul 2019 - Feb 2022
.NET is a cross-platform runtime for cloud, mobile, desktop, and IoT apps.
Role in this project:
Back-end Developer & QA Engineer / Test Automation Engineer
Back-end Developer & QA Engineer / Test Automation EngineerContributions:18 reviews, 16 commits, 15 PRs in 2 years 7 months
Contributions summary:Matthew primarily contributed to the .NET runtime by implementing and testing asynchronous methods for the `System.Diagnostics.Process` class. They introduced `WaitForExitAsync` and added comprehensive unit tests to ensure the functionality and reliability of the new asynchronous methods, including tests for cancellation and various process scenarios. Furthermore, the user removed unused local variables and methods across the code base in multiple areas of the repository, including System.IO.FileSystem, System.IO.Ports and System.Private.Xml which indicates the user's involvement in maintaining and improving the codebase's quality and maintainability.
dotnetruntimelinuxcsharpxamarin
adamhathcock/sharpcompress
Jul 2018 - Jul 2018
SharpCompress is a fully managed C# library to deal with many compression types and formats.
Role in this project:Back-end Developer & Test Automation Engineer
Back-end Developer & Test Automation EngineerContributions:27 commits, 3 PRs, 5 comments in 2 days
Contributions summary:Matthew focused on improving the stability and maintainability of the SharpCompress library. Their contributions included refactoring code to avoid performance bottlenecks by preventing exceptions in hot paths and adding unique scratch paths for tests to avoid test failures. They also made improvements to the test suite, including refactoring tests to use the ReaderFactory, validating Dispose calls, and fixing stream leaks, ensuring the tests were robust and reliable. This work demonstrates a focus on both optimizing performance and improving the quality of the testing infrastructure.
dealdeflatexzgzipc-sharp
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