I am a software engineer at Facebook. My current focus is on improving availability and operational efficiency of Facebook’s large-scale distributed systems.

Before Facebook, I was director of engineering in Microsoft’s cloud and enterprise division, Redmond, WA, USA, where I founded the Tools for Software Engineers team to accelerate Microsoft’s engineering velocity, more specifically to minimize the cycle time of the inner loop from code review, via build, code-analysis and test, to deployment.
Before venturing into product groups, I lead the Research in Software Engineering (RiSE) group and worked for many tools that Microsoft ships, including Linq, CodeContracts, Task Parallel Library, IntelliTest and SpecExplorer.
I co-developed the experimental program verifiers Spec# and VCC. I am a a recipient of the 2016 Mills Award.


Distributed systems, focusing on making distributed systems scale; programming languages, ranging from language design to runtimes; software development tools, ranging from build, via program verification and analysis, to automated test; and software engineering analytics, ranging from collecting data to prediction.