When you purchase a subscription plan, you are allotted a quota depending on the payment plan. When you make more API requests than your quota allows, rather than blocking requests which are over your quota, we apply overage billing. This means that you’ll never have any unexpected downtime. Requests over your quota are charged at an overage-fee rate.To set a spending limit, head to the Developer Dashboard and set a hard spending limit. Set this to $0 if you want to disable overage. Further details on the mechanics of overage are available here.Overage billing is not available on the free plan. To start using overage, please upgrade first to one of the paid plans.