Credit card verification will be done by making a temporary minimum charge on the card and then the customer should verify the what is charge from there credit card statement.
You can use CreatePayment with autocomplete set to false. This will verify the card (or return an error if it’s an invalid card etc) and the payment can be completed at a later time. I believe this would put the funds in a PENDING state on the customer’s card, until it is captured (or voided).
It’s confusing, So we take authorization payment and that will show in pending state. Later when we decide the charges it will be Charged?
Yes, autocomplete == false on Square’s side will mark the payment as “APPROVED”. Once you complete the payment (using CompletePayment) it would change to “CAPTURED” and actually charge the customer. If you fail to complete the payment within the time frame (by default 7 days), or if you explicitly call CancelPayment) then the payment will be marked as “CANCELED” and the customer would not be charged.
Hello, I’m filling out the Create Payment in the API Explorer. Where is the field for inputting the credit card number, CVV and expiration date?
I think there might be some gap in my understanding of the API. Can a payment stand alone to trigger a credit card transaction or does a payment need to be created as part of an Order?
With Square you will first need to use the Web Payments SDK to generate the source_id that is used in the payment request. Also stand alone payment created with the Payments API will generate an order if you don’t want to create an order prior to the payment and pass it into the payment request. 
Thanks for the help. Is there anywhere I can look to see all the API calls that are triggered when executing this sample application on the SDK page?
Hello, I am trying to run the quickstart program you gave me here: https://github.com/square/web-payments-quickstart
I’m running into a script error when executing ‘npm run dev’ on the command line. See attached.
It’s some error relating to the script being written for linux environment but I cannot find the script anywhere in the folder? What is the script name? Do you have a version written for windows 10?