Hello, All accounts can validate 1,500 addresses per hour via the api. If you purchase 1,000,000 validations or more, Bulk Email Checker will grant your account 2,500 addresses per hour. If you purchase 10,000,000 validations or more Bulk Email Checker will grant your account 4,000 addresses per hour. 4,000 validations per hour is our maximum api hourly limit. The hourly limits granted depends entirely on validation package size purchased. Requests for increases above our 4,000 addresses per hour limit will be reviewed and granted on an individual basis. Please contact us to inquire.