Account validation is the process of checking that a bank account number is correct and usable before money is sent to it or pulled from it. It is closely related to, and often used interchangeably with, account verification; the full explanation of the methods and why businesses use them is in the Bank Account Verification entry.
Validation can mean several levels of check. The lightest is a format check: an IBAN carries two check digits that catch most typing errors, and a US routing number has its own check digit. A format check proves only that the number could exist, not that the account is open. Stronger checks ask the receiving bank or a data service whether the account is open and active, or send small test deposits that the account holder must confirm.
Name-matching services go a step further by comparing the account holder's name with the name the payer typed, such as the EU's Verification of Payee. These checks reduce failed payments and help stop authorized push payment fraud.