ShipIt! Presents: Keeping Developers Happy with a Fast CI

At Shopify, we run automated continuous integration (CI), like executing tests or code linting, on every git push. While we all agree that this should be fast, it's not an easy task if you have more than 170,000 tests to execute. Slow CI systems are often responsible for making frustrated developers. Keeping these systems fast requires an ongoing effort. Our developers were frustrated and that was the reason to run a dedicated project improving the speed of Shopify’s CI that reduced the p95 of Shopify’s core monolith CI from 45 minutes to 18.