Stripe API request working with Postman but failing with Apex Rest Callout

Question

I'm trying to make a callout to a Stripe Api with Apex. I made the exactly same request in Postman with the same Http configuration and have this working well. But when running it with Apex i get a Http 400 (Bad Request) with this error message:

{
  "error": {
    "message": "This property cannot be expanded (data).",
    "type": "invalid_request_error"
  }
}

What I want to do is to query a list of Payment Intents from stripe and expand the balance transaction stored in the payment charge data. And here is how I do it

Http http = new Http();

HttpRequest request = new HttpRequest(); 
request.setHeader('Authorization', 'Bearer Token');  
request.setHeader('Content-Type', 'application/x-www-form-urlencoded');

String payload = 'expand[]=data.charges.data.balance_transaction';

request.setMethod('GET');

request.setEndpoint(API_ENDPOINT + '/v1/payment_intents');

request.setBody(payload);

HttpResponse response = http.send(request);

System.debug(response.getBody());

Can anyone help me please to understand what I am missing here?

Answer 1

You need to set the Authorization token correctly. sToken (SessionID)

request.setHeader('Authorization', 'Bearer ' + sToken);

Also could you check your payload ? I believe you are able to make the call but the payload is incorrect.