Customer Self-Serve Invoice Downloads

Rather than forcing customers to email customer support for PDF invoices, SuperGST provides a secure storefront App Proxy endpoint:

https://yourstore.com/apps/invoices?order_id={{ order.id }}

When a customer requests their invoice:

• 1
  Shopify validates the customer's request using cryptographic HMAC signatures.
• 2
  The App Proxy checks whether the invoice has finished generating. If processing is underway, an animated status page informs the buyer that the invoice is being prepared and auto-refreshes.
• 3
  Once generated, SuperGST issues an authorized, time-limited secure download link for the customer's browser to retrieve the official PDF invoice.
• 4
  The customer's browser immediately downloads the official print-ready PDF invoice.

SuperGST integrates directly with Shopify's native notification system. When an invoice PDF is compiled and saved, SuperGST sets the following order metafield:

namespace: "custom", key: "gst_invoice_generated", value: true

You can use this trigger inside your Shopify Order Confirmation or Shipping Confirmation Liquid email templates:

```liquid

{% if order.metafields.custom.gst_invoice_generated %}

<a href="https://{{ shop.domain }}/apps/invoices?order_id={{ order.id }}" class="button">

Download Official GST Invoice

</a>

{% endif %}

`

Because download links are served dynamically through the App Proxy, merchants never have to worry about broken or expired static file URLs in emails.