Andrew Arnott
Software Engineer at Microsoft
Longmont, Colorado, United States
Summary
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RockstarAndrew Arnott is a seasoned software engineer with 19 years of experience, currently contributing to the Visual Studio Platform at Microsoft and actively maintaining a wide range of open-source .NET projects. He combines deep backend expertise—threading, JSON-RPC, serialization and P/Invoke—with DevOps and build automation skills, having modernized CI/CD and cross-target builds for multiple repositories. His work includes performance-focused contributions to MessagePack-CSharp and protocol extensions for vs-streamjsonrpc, reflecting a knack for both low-level optimization and robust API design. Based in Longmont, Colorado, he often straddles product-shipping responsibilities and community-facing OSS maintenance, from StyleCop analyzers to .NET runtime touches. Notably, he contributes pragmatic fixes that clarify cancellation semantics and build reproducibility—small changes that save teams hours of debugging. He also signals a playful openness to crypto donations, underscoring a long-standing involvement in FOSS culture.
19 years of coding experience
Github Skills (71)
nuget10
libgit210
multithreading10
wp-api10
winapi10
asp-net10
libgit2sharp10
automation10
csproj10
code-analysis10
build-automation10
azure-pipelines10
threaded10
ws-api10
runtimes10
Programming languages (23)
Github contributions (5)
MessagePack-CSharp/MessagePack-CSharp
Sep 2018 - Jan 2023
Extremely Fast MessagePack Serializer for C#(.NET, .NET Core, Unity, Xamarin). / msgpack.org[C#]
Role in this project:
Back-end Developer & Performance Engineer
Back-end Developer & Performance EngineerContributions:47 releases, 326 reviews, 1021 commits in 4 years 4 months
Contributions summary:Andrew primarily contributed to improving the performance of the MessagePack-CSharp library, as the primary goal of this project is to have a fast MessagePack serializer. They focused on optimizing serialization and deserialization for various numeric and primitive types (int, sbyte, etc.). The contributions include adding new features such as the handling of memory and the incorporation of various data structures for efficiency. Additionally, they implemented changes to support .NET 6 specific APIs.
dotnetmsgpackserializationmessagepacknet-core
microsoft/CsWin32
Dec 2020 - Jan 2023
A source generator to add a user-defined set of Win32 P/Invoke methods and supporting types to a C# project.
Role in this project:Back-end Developer
Back-end DeveloperContributions:31 releases, 151 reviews, 724 commits in 2 years 2 months
Contributions summary:Andrew contributed to the Microsoft/cswin32 repository by expanding a template for Microsoft.Windows.Sdk.PInvoke.CSharp, including the modification of the file `azure-pipelines/variables/InsertVersionsValues.ps1`. This involved updating package dependencies and adding support for the Windows SDK Win32 API Source Generator as well. The contributions also covered fixing the build of release configurations and implementing the correct use of inline arrays in the system.
roslyndotnetwindowsdefinedcsharp-sourcegenerator
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