PayPal Payments API "Incoming JSON request does not map to API request" - paypal

Question

I'm trying to perform a super-simple call to the PayPal Payments API.
{
"intent":"sale",
"payer": {
"payment_method":"credit_card",
"funding_instruments": {
"credit_card_token": {
"credit_card_id":"CARD-XXXXXXXXXXXXXXXXXXXXXXXX"
}
}
}
}
I've tried adding/removing various parts of the request, and I've had minimal success, but inevitably, I come across an error of "Incoming JSON request does not map to API request MALFORMED_REQUEST".
According to the documentation, these are the only required parameters, but I've tried different funding_instruments, adding payer_info, adding transactions, using credit_card_token and credit_card... nothing seems to work, and the documentation is useless for troubleshooting.
Is there a way to be able to determine WHY this is a malformed request? Most of the documentation I am coming across uses payment_method: paypal instead of credit_card. What are better ways for me to troubleshoot why this request is failing?

Answer 1

There are a few things to consider first. Are you in the US?
if not you will need to consider if your country can use the API. You can find Information of which countries can use the API here https://developer.paypal.com/docs/integration/direct/rest/country-codes/
You might also need to validate your json. I've tested what you have posted here, but you might not be generating the information properly in your app. check the output and make sure that it is valid json--MALFORMED_REQUEST is an indicator that required key/value pairs are missing or that the json is not valid... this website will help you validate the json output https://jsonlint.com/
check your headers carefully to ensure that you have a properly formatted header request header. you can check your headers against the api requirements here https://developer.paypal.com/docs/api/overview/#http-request-headers
paypal notes that they provide an error code as a json string for errors arising in this manner, and that details may or may not be provided in the response. error response codes are in the 400 and 500 ranges and correspond to error messages (these are listed on the headers page given above)
However, given your error message which is not listed i'm going to guess that you are missing required key/value pairs in your json...
paypal says that INTENT AND PAYER OBJECTS ARE REQUIRED, but the example payment that they give lists a great deal of information that your sample json is missing--
among those items are the transaction details which are required...
per paypal's api docs "Include payer, transaction details...
paypal api documentation gives examples of of the required payer and intent objects here https://developer.paypal.com/docs/api/payments/
restrictions are further placed on direct credit card payments: they may only be accepted from the UK or US, and only if the account is payment pro enabled...
options for avoiding this issue are:
1) paypal classic api direct payments--https://developer.paypal.com/docs/classic/paypal-payments-pro/integration-guide/direct-payment/
2) braintree direct: https://www.braintreepayments.com/products/braintree-direct
3) or payflow pro: https://developer.paypal.com/docs/classic/products/payflow

Answer 2

Funding instruments in an array so the request should be something like below.
Transaction is required as that's the only way you will be able to specify what amount you are capturing.
{
"intent":"sale",
"payer": {
"payment_method":"credit_card",
"funding_instruments": [ {
"credit_card_token": {
"credit_card_id":"CARD-27V22453CF057824JLLDIA7Q"
} }
]
},
"transactions": [
{
"amount": {
"total": "30.11",
"currency": "GBP",
"details": {
"subtotal": "30",
"tax": "0.07",
"shipping": "0.03",
"handling_fee": "1.00",
"shipping_discount": "-1.00",
"insurance": "0.01"
}
}
}]
}