A serverless browser moves the work of running and maintaining the browser to a service provider. In Browserbase'sexplanation, an automation script requests a remote Chromium instance, connects through the browser's control protocol, performs its task, and ends the session. The developer still supplies the automation logic.
Giving each task a fresh browser also makes leftover cookies and other session state an explicit choice. The provider handles browser provisioning and cleanup, while the application controls which tasks to run. This separates maintaining a browser fleet from writing the scripts that use it.