Sheng Wu didn’t plan to write the code that underpins some of the biggest tech companies in the world. It was 2015, and he was just looking for a fun way to teach a friend how to program. He set up an open source project, looking to answer a question plaguing him in his day job: How to coordinate six unruly vendor companies with the internal system of his client, the telecommunications giant China Unicom? Wu knew he needed to build some kind of distributed system, so they could all work at the same time and see where errors were originating.

“It was chaos, and everyone blamed the others’ faults when the system went down,” said Wu. “So we thought: Maybe there is a technological solution we can build, at least to find the right one to blame.”