Direct debit can easily done by creating some CSV-style file without additional charges using FinTS/HBCI.
For most SaaS/e-product models "direct debit" is not an option because a customer can do a refund without a reason for at least 6 weeks. It also has no CVV2, so you can just abuse some charity bank details for a direct debit purchase. Good luck dealing with fraud.
For most SaaS/e-product models "direct debit" is not an option because a customer can do a refund without a reason for at least 6 weeks. It also has no CVV2, so you can just abuse some charity bank details for a direct debit purchase. Good luck dealing with fraud.