David Justo
Senior Software Engineer at Microsoft
Seattle, Washington, United States
Summary
🤩
Rockstar🎓
Top SchoolDavid Justo is a Senior Software Engineer with 11 years of experience building developer tools and cloud services, currently focusing on AddressSanitizer and the Microsoft STL within Visual C++ at Microsoft. He combines deep systems and runtime expertise—spanning C++, ASan, and durable serverless orchestration—with hands-on DevOps and control-plane work that enabled Azure Functions’ Flex Consumption SKU. A regular open-source maintainer and contributor, he has materially improved Durable Task and Durable Functions observability and reliability, and helped upstream Microsoft’s ASan to LLVM. David is customer-focused, frequently engaging in on-call incident resolution and driving migrations to more secure infrastructure. He also brings research-rooted rigor from his MS work on compiler optimizations and a track record of turning quadratic runtime complexities into linear solutions across multiple SDKs. Based in Seattle, he’s as comfortable reviewing third-party OSS contributions as he is diving into race conditions and storage integrations in distributed systems.
11 years of coding experience
9 years of employment as a software developer
Bachelor's Degree, Computer Science, Bachelor's Degree, Computer Science at University of California, San DiegoMaster's degree, Computer Science, Master's degree, Computer Science at University of California San Diego
Spanish, German, French, English
Stackoverflow
1reputation
0reached
0answers
0questions
Github Skills (20)
azure-application-insights10
azure-storage10
testing10
net10
azure-functions10
dotnet10
microsoft-azure10
durable-functions10
netframework10
asp-net10
dotnet-core10
azure10
csharp10
app-insights10
serializer9
Programming languages (17)
Github contributions (5)
Azure/azure-functions-durable-extension
Mar 2020 - Jan 2023
Durable Task Framework extension for Azure Functions
Role in this project:
Back-end Developer
Back-end DeveloperContributions:15 releases, 647 reviews, 177 commits in 2 years 10 months
Contributions summary:David primarily contributed to the core functionality of the Durable Task Framework extension for Azure Functions. Their work involved extending the orchestration shim to handle new asynchronous actions, such as SignalEntity and ScheduledSignalEntity, and ensuring compatibility for existing features, like orchestration client bindings. Furthermore, the user implemented enhancements, including structured logging for Linux dedicated plans and the addition of Application Insights tags for orchestrators and entities, improving observability. These changes demonstrate a focus on improving the framework's capabilities and monitoring.
azure-functions
Azure/durabletask
Oct 2020 - Jan 2023
Durable Task Framework allows users to write long running persistent workflows in C# using the async/await capabilities.
Role in this project:Back-end Developer
Back-end DeveloperContributions:18 releases, 487 reviews, 44 commits in 2 years 3 months
Contributions summary:David made several code changes focused on improving the reliability and maintainability of the Durable Task Framework. They enforced the correct order of events within orchestration work items, removed potential null pointer exceptions, and updated the versions for the project's release. Additionally, the user reverted a change related to storage IO optimization, indicating involvement in performance-related considerations. They also addressed a race condition related to singletons with external events and made changes to the Azure Storage integration.
asynccsharp
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