What is scale to zero?
Scale to zero means an app releases its computing resources when nobody is using it and starts again on the next request. The trade-off is the cold start: the first request after a quiet period takes longer while the app wakes up.
Why platforms do it
Most internal tools and side projects are idle most of the day. Keeping a server running for an app nobody is using wastes resources and money. Scaling to zero lets a platform host many mostly-idle apps sustainably, then scale each one up automatically when traffic arrives.
What it means for your app
Apps deployed on White Ghost scale to zero when idle and autoscale with traffic. In practice: no babysitting and no capacity planning, in exchange for a cold start on the first request after inactivity. For dashboards, internal tools, and shared apps, that trade is almost always worth it.