Tokenization is a security mechanism that protects sensitive data, such as credit card accounts. Instead of storing the account details locally, merchants are issued a token that replaces the sensitive payment details with a series of randomly generated characters, called a token. The token is linked to the payment details in a secure vault hosted by the merchant's payment provider. When submitting a transaction, the merchant can simply submit the token with the transaction. The payment provider will then replace the token with the underlying payment details before forwarding the transaction to the next stop in the processing chain.
By storing tokens, merchants can handle card on file and recurring payments without needing to store sensitive payment details themselves. This reduces the merchant's PCI DSS scope and eliminates the possibility of malicious actors gaining access to credit card details in a data breach affecting the merchant.