incomingPayment

The monetization event’s incomingPayment attribute can be used to verify the receipt of a payment. Today, the monetization event fires when the Web Monetization agent successfully creates an outgoing payment request at the Web Monetization provider. Since it’s only a request to send an outgoing payment, there’s no guarantee at this point that a payment has been received.

The incomingPayment attribute returns the URL that represents the incoming payment at the Web Monetization receiver. The returned value is the value it was initialized with. By querying the URL, you can get the receivedAmount.

Example

/** @type {MonetizationEvent} event */
async function verifyPayment(event) {
  // Legacy receivers don't support returning incoming payment URLs
  if (!event.incomingPayment) {
    throw new Error('No incoming payment URL')
  }

  const response = await fetch(event.incomingPayment, {
    method: 'GET',
    credentials: 'same-origin',
    mode: 'same-origin',
    cache: 'no-cache',
    headers: {
      'Content-Type': 'application/json',
    },
  })

  if (response.ok) {
    // The incoming payment was fetched successfully
    const { receivedAmount } = await response.json()
    const { amount, assetCode, assetScale } = receivedAmount
    console.log(`Received ${assetCode}${amount / Math.pow(10, assetScale)}.`)
  }
}

Specifications

Specification
Web Monetization #incomingpayment-attribute