About Terms, Conditions and EULAs
This article discusses the use of terms and conditions and end-user license agreements.
As the merchant and seller of record, FastSpring purchases products and services from you - the publisher/creator/provider - and re-sells the products or services to the end customers. Our status as the merchant of record provides many advantages to you, such as allowing us to handle all collection and remittance of sales tax and VAT. This arrangement frees up your time and resources since you do not have to deal with those issues.
The arrangement also means that any terms and conditions associated with a payment transaction processed by FastSpring need to be FastSpring's terms and conditions (as opposed to your terms and conditions or your End User License Agreement/EULA).
Therefore, you should include any necessary terms and conditions for using the product--and EULA--either on your website, or else perhaps in the installer of your products where applicable.
The following order flow illustration may be helpful.
The following diagram illustrates the relationships between FastSpring, you (the seller in this context), and the customer, from the perspective of GDPR compliance.