I'd like to test my API donation form, but I don't want to record real transactions in Luminate Online which I would have to refund.
Submit the df_preview parameter as part of the API call that your API donation form will make.
This will still evaluate the success of the API call, but it will not create a transaction in Luminate Online.
Please note, the fact that the df_preview parameter is included in the API call is what is pertient, the value submitted is not important. This means that submitting df_preview=false will still be treated as a request for the preview behavior.