Is zero value authorization supported by SEPA Direct Debit?

While zero authorization is technically possible, it usually adds little value because in such a case, Adyen would only store the IBAN but not send anything to the issuer to validate it. 

Instead, we recommend that you first authenticate the customer with an IBAN-based payment method that requires strong customer authentication where possible. This way, Adyen ensures that the customer's IBAN is valid and that they have access to it rightfully. 

It's also essential to provide your customer with a fallback mechanism to provide their payment details (IBAN and Name) so they can sign up with an IBAN of their choice. You can do so using PayByLink, where a customer can fill in the IBAN and name, or via a manual/offline process during which you collect the IBAN and name of the customer to enroll.

We also advise charging your customer a minimum amount of 0.1 EUR, which you can refund once the funds have been paid out to your account. This ensures the IBAN is both stored and validated.