All plans enforce a hard limit once you reach your monthly allowance — see Quotas. Relaybase does not automatically bill for overage.
Plans
Plans and usage
Relaybase provides different plans based on your validation requirements. Your available plan determines the resources and usage limits available to your account.
Webhooks and bulk CSV upload are listed as Pro/Enterprise features but are currently under development — see Bulk Email Validation and Webhooks for current status.
You can review the available plans on the Relaybase website.