How PlanetScale makes schema changes

One of our early goals when building PlanetScale was to make the absolute best schema change process for engineering teams. We've been iterating on this for the past 3 years and are increasingly happy with how easy it is to change our application's schema.Our main API is a Ruby on Rails application that is connected to two PlanetScale databases. One of these databases contains the majority of our business and user data. The other is a larger, sharded database built to handle the massive scale needed to power PlanetScale Insights.