To connect PayPal Business and Paperform, we need to create two REST API apps in PayPal's developer portal. One app will be in "Sandbox" mode and can be used for testing purposes without taking actual payments. The second app will be in "Live" mode and will be used for real payments.
Under “REST API Apps”, create a new Merchant app called “Paperform”.
After the app has been created, you’ll be redirected to the Sandbox details of the app. In your Paperform Account Services under Payment Accounts click the “Connect PayPal Business Account” button and enter the required Sandbox details. You can use the sandbox account for testing purposes (it won’t process live payments).
After you have added the Sandbox account, you need to add a Live account. To do this, go back to the main applications page, and ensure "Live" is toggled on.
Create another REST API app called Paperform, and then navigate to your Paperform Account Services, click the button "Connect PayPal Business" again, and enter the details for the live app. Make sure you select “No” for the option “Are these Sandbox details?” during the setup on Paperform.
Use PayPal on a form
After you have connected your PayPal account, you can then use it to take payments on your forms by going to Configure → Payments in the form editor and selecting the appropriate Payment account from the dropdown field. You can use the Sandbox account to test your form and submissions or use the Live account to capture actual payments.
Gotchas
Paperform forms do not support using PayPal for subscriptions. If you would like to set up subscriptions, you can do so with Braintree or Stripe.
When setting up the integration, make sure there aren't any typos or blank spaces in the credentials as it needs to be exactly the same credentials in your Paypal Business account.