Mayuki Sawatari
Software Engineer at Cysharp
Tokyo, Japan
Summary
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RockstarMayuki Sawatari is a seasoned Software Engineer based in Tokyo with 21 years of hands-on experience building and hardening backend systems and developer tooling. A Microsoft MVP for Developer Technologies and active open-source maintainer, Mayuki has contributed substantive fixes and performance-minded improvements to high-profile C# projects such as MessagePack-CSharp, MagicOnion, and the zero-allocation ConsoleAppFramework. Their work emphasizes reliability and test automation—adding unit tests, refining code generation, and improving hosting/configuration integration—often focusing on edge cases like generic type formatters and Unity-specific binary search correctness. Comfortable across full-stack extension work (e.g., GitHub for Visual Studio) and deep systems-level optimizations, they blend pragmatic engineering with attention to developer experience. Colleagues can expect a meticulous contributor who prefers measurable fixes—skipping unnecessary writes, normalizing outputs, and upgrading hosting stacks—to deliver stable, maintainable libraries.
21 years of coding experience
Github Skills (27)
unit-testing10
git10
serializer10
github10
binary-search10
net10
in-memory-database10
dotnet10
data-serialization10
memory-database10
serialization10
netframework10
asp-net10
console-application10
code-generation10
Programming languages (9)
Github contributions (5)
Cysharp/MagicOnion
Aug 2019 - Jan 2023
Unified Realtime/API framework for .NET platform and Unity.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:2 releases, 31 reviews, 766 commits in 3 years 5 months
Contributions summary:Mayuki primarily contributed to the backend framework, enhancing its hosting and configuration options. The commits focused on integrating the MagicOnion framework with Microsoft.Extensions.Options, enabling more flexible and configurable server setups. Additionally, the user implemented tests for the hosting functionality to validate the changes, ensuring the stability of the system.
api-frameworkdotnetunityswaggergrpc
mayuki/Cocona
Jan 2020 - Jan 2023
Micro-framework for .NET console application. Cocona makes it easy and fast to build console applications on .NET.
Role in this project:Back-end Developer
Back-end DeveloperContributions:8 releases, 397 commits, 114 PRs in 3 years 1 month
Contributions summary:Mayuki primarily contributed to the development of unit tests for the .NET console application framework, Cocona. Their commits focused on adding comprehensive unit tests for parameter binding, specifically addressing scenarios involving arguments, options, arrays, and lists. These changes indicate a focus on ensuring the robustness and reliability of the core functionality of Cocona by validating the correct handling of different parameter types and combinations. The user's work also included refactoring existing code to improve the framework's maintainability.
console-applicationdotnetmicro-frameworkcsharpcli
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