Adrian213

Hello,

If you haven't sorted this already, you need to use Javascript to generate the date - won't work with PHP. I believe the date is used by Google to send the review to the cusomer so it needn't be too specific, in this example I've just added 7 days to the current date:

<script src="https://apis.google.com/js/platform.js?onload=renderOptIn" async defer></script>
<script>
  window.renderOptIn = function() {
    window.gapi.load('surveyoptin', function() {
      const deliveryDate = new Date();
      deliveryDate.setDate(deliveryDate.getDate() + 7);
      function formatDate(date) {
        var d = new Date(date),
        month = '' + (d.getMonth() + 1),
        day = '' + d.getDate(),
        year = d.getFullYear();

        if (month.length < 2) 
               month = '0' + month;
        if (day.length < 2) 
            day = '0' + day;
        return [year, month, day].join('-');
    }
      
      window.gapi.surveyoptin.render(
        {
          // REQUIRED FIELDS
          "merchant_id": 12345678,
          "order_id": "{orderId}",
          "email": "{customerEmailAddress}",
          "delivery_country": "GB",
          "estimated_delivery_date": formatDate(deliveryDate)
          // OPTIONAL FIELDS
          //"products": [{"gtin":"GTIN1"}, {"gtin":"GTIN2"}]
        });
    });
  }
</script>

Hope it helps