问题
When i'm using sandbox account for drop-in form of braintree then card fields and paypal button is visible.
But on production account API credentials then paypal button is not visible.
回答1:
Full disclosure: I work at Braintree. If you have any further questions, feel free to contact support.
My suspicion is that your production account is not configured to accept PayPal, which will prevent the button from even showing up in the Drop-in. Ensure that you have configured and verified a PayPal Business Account, and that it is enabled in the Control Panel. Once it is enabled, the button should automatically appear in instances of your Drop-in UI, or you can include it separately.
If you have any trouble setting up your account, or if your account is enabled for PayPal and the button still doesn't show, please reach out to Braintree support.
来源：https://stackoverflow.com/questions/39138929/why-in-braintree-paypal-button-is-not-visible-using-drop-in-form-in-productionl