https://help.developer.intuit.com/s/question/0D50f00006KgUE0CAN/are-customer-custom-fields-as-found-in-quickbooks-online-advanced-available-via-the-api-i-cant-find-any-reference-to-them-in-the-documentation-or-when-querying-customer-objects
Are Customer Custom Fields (as found in Quickbooks Online ...
Jun 6, 2019 ... In Quickbooks Online Advanced, custom fields can be added to customers. I can't find any documentation for this feature in the API Reference.