Ryosuke Niwa
Software Engineer at Apple
San Francisco, California, United States
Summary
🤩
Rockstar🎓
Top SchoolRyosuke Niwa is a senior software engineer with 16 years of experience focused on browser engines, currently shaping WebKit architecture at Apple and serving as an active WebKit reviewer and contributor for over a decade. He has driven performance benchmarking and monitoring at scale—authoring the original Speedometer 1.0, helping launch Speedometer 2.0, and building CI-integrated regression detection—and implemented key WebKit features including v1 Custom Elements, parts of v1 Shadow DOM, and ES6 class support in JavaScriptCore. His open-source work spans test-suite hardening (web-platform-tests), WPEWebKit front-end porting, and LLVM/Clang static-analyzer improvements to catch memory-safety issues in WebKit code. Comfortable both in low-level compiler checks and high-level DOM/HTML standards discussions, he also played a formative role in HTML editing and undo/transaction specifications and continues to influence W3C/WHATWG specs. Based in San Francisco with a UC Berkeley EECS background, he blends rigorous engineering with long-term stewardship of web platform correctness and performance.
16 years of coding experience
2 years of employment as a software developer
BS Electrical Engineering and Computer Sciences, BS Electrical Engineering and Computer Sciences at University of California, BerkeleyDiablo Valley College
English, Japanese
Github Skills (19)
javascript10
c-language10
static-analysis10
llvm10
testing10
css10
webkit10
html10
shadow-dom10
memory-safety10
custom-element10
webtest10
cprogramming-language10
dom9
web-standards9
Programming languages (9)
Github contributions (5)
WebPlatformForEmbedded/WPEWebKit
Jul 2009 - Oct 2022
WPE WebKit port (downstream)
Role in this project:
Front-end Developer
Front-end DeveloperContributions:4432 commits in 13 years 4 months
Contributions summary:Ryosuke primarily focused on updating and refactoring tests related to web platform tests (WPT). Their contributions involved modifications to test cases for shadow DOM and custom elements, incorporating the latest WPT changes. The user also addressed issues related to CSS and JavaScript functionality in these tests, ensuring that the test suites correctly validated WebKit's behavior, as demonstrated by the addition of test cases.
wpedownstreamwebkit
web-platform-tests/wpt
Jun 2012 - Jan 2023
Test suites for Web platform specs — including WHATWG, W3C, and others
Role in this project:QA Engineer / Test Automation Engineer
QA Engineer / Test Automation EngineerContributions:65 reviews, 89 commits, 176 PRs in 10 years 8 months
Contributions summary:Ryosuke primarily contributed to the web platform tests (WPT) repository, focusing on identifying and fixing flakiness in existing tests, as well as adding new test cases. Their work involved modifying existing tests to improve reliability, particularly in areas such as worker performance, shadow DOM event dispatching, and focus navigation. Furthermore, the user added tests related to mixed content blocking and viewport dependent media queries within iframes, enhancing the test suite's coverage of various web platform features.
microsoft-edgetest-runnerspecssafarifirefox
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