Static Lists vs Dynamic Lists: What's the Difference?

A static list is a fixed set of contacts, added manually or through a one-time import, that doesn't change unless someone actively adds or removes members. Once built, it stays exactly as it was until manually edited again.

A dynamic list, sometimes called a smart list, is defined by a set of rules or filter criteria rather than a fixed membership - anyone who matches the criteria, such as a specific score range, a tag, or activity within a time window, is automatically included, and automatically removed the moment they no longer match.

Static lists are predictable and simple - useful for a one-time send to a specific, hand-picked group - but go stale the moment the underlying facts change, since nobody comes back to update it. Dynamic lists stay accurate automatically, always reflecting current reality rather than a snapshot from whenever the list was built, which is what makes them the right choice for anything ongoing - a nurture segment, an active-customer list - where membership is expected to keep shifting over time.