Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

The PaymentRequest event handler onmerchantvalidation is invoked when the merchantvalidation is fired, indicating that the payment handler (e.g., Apple Pay) requires the merchant to validate themselves.

This is usually the first event to be fired, and the user won't be able to proceed with a payment until the merchant validate themselves.

This event is not be fired by all payment handlers. In particular, it's used by Apple Pay.


paymentRequest.onmerchantvalidation = eventHandlerFunction;


An event handler function which is to be called whenever the merchantvalidation event is fired at the PaymentRequest, indicating that the payment handler requires the merchant to validate themselves as allowed to use this payment handler.


An example merchant validation handler for the PaymentRequest object request looks like this:

request.onmerchantvalidation = ev => {
  ev.complete(async () => {
    const merchantServerUrl = window.location.origin +
        '/validation?url=' + encodeURIComponent(ev.validationURL);
    // get validation data, and complete validation;
    return await fetch(merchantServerUrl).then(r => r.text());

const response = await;

For more information, see Merchant Validation in Payment processing concepts.

Browser compatibility

BCD tables only load in the browser