When a new user signs up, you likely want to be notified quickly. Typically, this might just be a message in Slack notifying you that a user has signed up.
To make this really easy, we've added a Notifications section to your dashboard. You enter a Slack webhook URL, and we'll notify you every time a new user signs up. You can also set different webhooks for your test and production environments, to avoid the long list of fake notifications (email@example.com, firstname.lastname@example.org, ...).
If you are looking for more advanced actions on user signup or other events, you likely want webhooks.