Call Logging and Javascript Error Handling

During the development stage of your custom checkout it's a good idea to review the checkout API call log located under the integration center menu. The call log will display the last 100 errors that occurred. You can also enable the log to record all calls. This can be very helpful to understand not only the operations your checkout is calling, the order of the operations, the data being submitted as parameters as well as the results your client received. Once you put your custom checkout into production you should make sure to turn off the log all calls setting so that only errors are logged. You can then review your call log periodically to see if any server side or client side errors are occurring.