Theo Yaung
Engineering Manager at Instagram
San Francisco, California, United States
Summary
👤
Senior🎓
Top SchoolTheo Yaung is an engineering manager with 11 years of experience leading large-scale developer tools and product teams across Meta, WhatsApp, and Microsoft, now managing engineering at Instagram from London. He combines deep systems and language-tooling expertise—spanning compilers, runtimes, IDEs and build tools—with hands-on product delivery for massive web and mobile applications. At WhatsApp he led a 20-person core web team, inaugurated design systems and tablet/foldable initiatives, and earlier drove Roslyn-era compiler work and Visual Studio features at Microsoft. He contributes to notable open-source projects including Moq (improving delegate handling) and React Native (iOS Inspector refactors), reflecting a practical blend of backend and mobile skill. Known for taking 0→1 products to launch while navigating large-scale infra migrations and multi-device end-to-end encryption sync, he excels at bridging engineering strategy and execution. Colleagues describe him as a pragmatic technical leader who refactors complexity into reusable tooling and reliable shipping cadence.
12 years of coding experience
22 years of employment as a software developer
Bachelor of Science Computer Science, Bachelor of Science Computer Science at Rice University
English
Stackoverflow
4,014reputation
734kreached
19answers
0questions
task-parallel-library
top-5%
async-await
top-1%
concurrency
top-1%
asynchronous
top-1%
Github Skills (33)
asynchronous10
objective-c10
ios10
mobile-development10
react-native10
net10
javascriptcore10
dotnet10
asp-net10
mocks10
delegates10
mocker10
mocking10
dotnet-core10
async-await10
Programming languages (6)
Github contributions (5)
devlooped/moq
Aug 2014 - Aug 2014
The most popular and friendly mocking framework for .NET
Role in this project:
Back-end Developer
Back-end DeveloperContributions:8 commits in 1 day
Contributions summary:Theo focused on enhancing the Moq mocking framework's delegate handling capabilities. They implemented parameter validation for curried delegates, which improves compatibility with extension methods and optimized delegate invocation in certain scenarios. The contributions involved refactoring code to improve the structure and reusability of the delegate-related logic within the framework. This work included moving code into extension methods and ensuring compatibility with lambda currying.
dotnetmocking
react/react-native
Dec 2016 - Jul 2017
A framework for building native applications using React
Role in this project:Mobile Developer (iOS)
Mobile Developer (iOS)Contributions:9 commits, 1 comment in 7 months
Contributions summary:Theo primarily focused on modifications and refactoring related to the Inspector functionality within the React Native framework, specifically targeting the iOS platform. Their work included refactoring interfaces, managing connections, and removing inspector logic that was not compatible with the system JSC on iOS. They also made changes to handle connection management within the InspectorPackagerConnection class.
reactandroidapp-frameworkiosmobile
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