We run lots (TK: number) of tests every time an engineer at Even makes a pull request. At first, running all of those tests was slow and required a bunch of complicated support code. But since I joined in October 2018, we totally revamped the way we run tests. This post tells the story of how we made testing faster and easier on our backend services. If you're interested in learning more, or want to help us improve testing our React Native mobile apps, we're hiring.