Overlay Checkout

Getting Started

Once you have a session id you can simply initialize the Checkout modal by using its constructor:

  • Include the Billwerk+ JavaScript SDK
    <script src="https://checkout.reepay.com/checkout.js"></script>
  • Open Checkout as a modal
    Overlay Initialise
    var rp = new Reepay.ModalCheckout(' YOUR SESSION ID HERE ');

You can test if the script is properly loaded by inspecting the Billwerk+ object in the console.

Notice that for Subscription sessions, the method name is ModalSubscription.

Overlay initialize for subscription sessions

var rp = new Reepay.ModalSubscription(' YOUR SESSION ID HERE ');


The modal fires a number of events which your application may subscribe to. In order to set up an event handler, use the .addEventHandler function, and pass it the type of event and the callback function:

Overlay Events

var rp = new Reepay.ModalCheckout(' YOUR SESSION ID HERE ');

rp.addEventHandler(Reepay.Event.Accept, function(data) {
	console.log('Success', data);

The possible event types which may be subscribed to are:

Overlay Event Types

AcceptFires once the transaction is successfully completed.
ErrorWhenever an error has occurred in attempting to finalize the transaction.
CancelThe user presses the cancel button.
CloseFires once the modal is closed. This event is independent of the previous, as none of the above events automatically close the modal - it is only ever done by the user clicking a button, whether the transaction was completed or not.

Each event responds with a signature of type:

Overlay Response Signature

  id: string;     // The current session id
  invoice: string;    // Invoice/charge handle
  customer: string;   // Customer handle
  subscription: string;   // Subscription handle
  payment_method: string; // Payment method if a new one is created
  error: string;    // The error code

To unsubscribe to events, use the .removeEventHandler method with the given event handler:

Overlay Remove Event Handler

var rp = new Reepay.ModalCheckout(' YOUR SESSION ID HERE ');




It is not mandatory to subscribe to events, however we strongly encourage it. The SDK will show helpful warnings in console if an un-handled even is fired (with the exception of the Reepay.Event.Error).

Once you have set up the Reepay.ModalCheckout object, with the event hanlders necessary, you are good to go!

Preloading the Modal

As an alternative to both initializing and loading the modal only once the backend to backend call is done and a session id is available, the two steps may be done separately and at different times in your code.

By calling the constructor without a session id, the modal is initialized in the background, however will remain hidden until the .show function is called and passed the required session id.

Overlay Preloading Modal

// Step 1: Initialize
var rp = new Reepay.ModalCheckout();  // No session id given

// ... Backend to backend call ... 

// Step 2: Load the modal 
rp.show(' YOUR SESSION ID HERE ');  // Call the .show function with the session id



For scenarios where the modal is opened automatically, we recommend initializing it directly to avoid potential timing issues.

Destroy the Overlay

Closing the modal is generally done by client interaction, which fires a Reepay.Event.Close event. However, you also have the option of programmatically closing the modal by calling the .destroy function:

Overlay Destroy

var rp = new Reepay.ModalCheckout(' YOUR SESSION ID HERE ');


This function call will also fire the Reepay.Event.Close event.

Hide the receipt page

The overlay mode supports replacing the receipt page displayed at the end of a successful payment with a blank page. As seen below, to make use of this feature, add showReceipt: false to the options object.

var rp = new Reepay.ModalCheckout(' YOUR SESSION ID HERE ', {showReceipt: false});

When preloading, simply pass the options object when calling the show method.

rp.show(' YOUR SESSION ID HERE ', {showReceipt: false});

Error Handling

The Billwerk+ Payments Checkout SDK throws a number of possible errors, described below. All the errors extend the global Error object.

Error NameDescription
RP_SessionTokenNotProvidedErrorIf the .show method is called without sending a session id. For more details on how to obtain a session id see the Introduction to Billwerk+ Payments Checkout Web SDK section.
RP_CheckoutNotInitializedTrying to access the iframe before it was initialized. This may happen when trying to preload the modal and call the .show function while the initializing is still happening.
RP_CallShowWhenAlreadyInitializedTrying to call .show when the modal is already initialized with a session id, either through constructor or a second call of .show.
RP_UnknownEventErrorTrying to handle an event that isn't defined. See the event section for a full list of possible events to subscribe to.
RP_HandlerNotAFunctionPassing a handler that isn't of type function to the .addEventHandler function.

What’s Next