How to Use Express Checkout for One-Time Payments.curl

DoExpressCheckoutPayment

Request 
-------
Endpoint URL: https://api-3t.sandbox.paypal.com/nvp
HTTP method: POST
POST data:
USER=insert_merchant_user_name_here
&PWD=insert_merchant_password_here
&SIGNATURE=insert_merchant_signature_value_here
&METHOD=DoExpressCheckoutPayment
&VERSION=86
&TOKEN=insert_token_value_here
&PAYERID=payer_id_value   #Identifies the consumer's account
&PAYMENTREQUEST_0_PAYMENTACTION=SALE    #The type of payment
&PAYMENTREQUEST_0_AMT=19   #The amount the consumer will pay
&PAYMENTREQUEST_0_CURRENCYCODE=USD     #The currency, e.g. US dollars

Response
--------
TOKEN=EC%123458644AS127201F
&SUCCESSPAGEREDIRECTREQUESTED=false
&TIMESTAMP=2012%2d02%2d02T20%3a48%3a42Z
&CORRELATIONID=123456101411b
&ACK=Success
&VERSION=86
&BUILD=2515991
&INSURANCEOPTIONSELECTED=false
&SHIPPINGOPTIONISDEFAULT=false
&PAYMENTINFO_0_TRANSACTIONID=12345337YG654084X
&PAYMENTINFO_0_TRANSACTIONTYPE=expresscheckout
&PAYMENTINFO_0_PAYMENTTYPE=instant
&PAYMENTINFO_0_ORDERTIME=2012%2d02%2d02T20%3a48%3a40Z
&PAYMENTINFO_0_AMT=19%2e00
&PAYMENTINFO_0_FEEAMT=0%2e85
&PAYMENTINFO_0_TAXAMT=0%2e00
&PAYMENTINFO_0_CURRENCYCODE=USD
&PAYMENTINFO_0_PAYMENTSTATUS=Completed
&PAYMENTINFO_0_PENDINGREASON=None
&PAYMENTINFO_0_REASONCODE=None
&PAYMENTINFO_0_PROTECTIONELIGIBILITY=Eligible
&PAYMENTINFO_0_PROTECTIONELIGIBILITYTYPE=ItemNotReceivedEligible%2cUnauthorizedPaymentEligible
&PAYMENTINFO_0_SECUREMERCHANTACCOUNTID=12345JW1234
&PAYMENTINFO_0_ERRORCODE=0
&PAYMENTINFO_0_ACK=Success

GetExpressCheckoutDetails

Request 
-------
Endpoint URL: https://api-3t.sandbox.paypal.com/nvp
HTTP method: POST
POST data:
USER=insert_merchant_user_name_here
&PWD=insert_merchant_password_here
&SIGNATURE=insert_merchant_signature_value_here
&METHOD=GetExpressCheckoutDetails
&VERSION=86
&TOKEN=insert_token_value_here

Response
--------
TOKEN=token_value
&CHECKOUTSTATUS=PaymentActionNotInitiated
&TIMESTAMP=2012%2d02%2d02T20%3a45%3a34Z
&CORRELATIONID=123458464cec
&ACK=Success
&VERSION=86
&BUILD=2515991
&EMAIL=sender_1234522775_per%40domain%2ecom
&PAYERID=1234512345MW8
&PAYERSTATUS=verified
&FIRSTNAME=Test
&LASTNAME=User
&COUNTRYCODE=US
&SHIPTONAME=Test%20User
&SHIPTOSTREET=1%20Main%20St
&SHIPTOCITY=San%20Jose
&SHIPTOSTATE=CA
&SHIPTOZIP=95131
&SHIPTOCOUNTRYCODE=US
&SHIPTOCOUNTRYNAME=United%20States
&ADDRESSSTATUS=Confirmed
&CURRENCYCODE=USD
&AMT=19%2e00
&SHIPPINGAMT=0%2e00
&HANDLINGAMT=0%2e00
&TAXAMT=0%2e00
&INSURANCEAMT=0%2e00
&SHIPDISCAMT=0%2e00
&PAYMENTREQUEST_0_CURRENCYCODE=USD
&PAYMENTREQUEST_0_AMT=19%2e00
&PAYMENTREQUEST_0_SHIPPINGAMT=0%2e00
&PAYMENTREQUEST_0_HANDLINGAMT=0%2e00
&PAYMENTREQUEST_0_TAXAMT=0%2e00
&PAYMENTREQUEST_0_INSURANCEAMT=0%2e00
&PAYMENTREQUEST_0_SHIPDISCAMT=0%2e00
&PAYMENTREQUEST_0_INSURANCEOPTIONOFFERED=false
&PAYMENTREQUEST_0_SHIPTONAME=Test%20User
&PAYMENTREQUEST_0_SHIPTOSTREET=1%20Main%20St
&PAYMENTREQUEST_0_SHIPTOCITY=San%20Jose
&PAYMENTREQUEST_0_SHIPTOSTATE=CA
&PAYMENTREQUEST_0_SHIPTOZIP=95131
&PAYMENTREQUEST_0_SHIPTOCOUNTRYCODE=US
&PAYMENTREQUEST_0_SHIPTOCOUNTRYNAME=United%20States
&PAYMENTREQUESTINFO_0_ERRORCODE=0

SetExpressCheckout

Request 
-------
Endpoint URL: https://api-3t.sandbox.paypal.com/nvp
HTTP method: POST
POST data:
USER=insert_merchant_user_name_here
&PWD=insert_merchant_password_here
&SIGNATURE=insert_merchant_signature_value_here
&METHOD=SetExpressCheckout
&VERSION=86
&PAYMENTREQUEST_0_PAYMENTACTION=SALE   #The type of payment
&PAYMENTREQUEST_0_AMT=19    #The amount the buyer will pay
&PAYMENTREQUEST_0_CURRENCYCODE=USD    #The currency, e.g. US dollars
&cancelUrl=http://www.yourdomain.com/cancel.html    #For use if the consumer decides not to proceed with payment 
&returnUrl=http://www.yourdomain.com/success.html   #For use if the consumer proceeds with payment