The email template uses the Liquid templating language.
The email template has the following Liquid objects available:
"shop_url": The first line of the shop address
"logo": The source URL of your shop logo
"shop_name": The name of the shop.
"title": Returns the product title
"content": Returns the HTML content for the Push Notification & Email :
Is available now!
Get it now before it goes out of stock again!
"image": Returns the variant image if one has been set. Use the URL property to include the image URL in your template.
"product_name": Returns the product name.
"price": Returns the variant's price.
"add_to_cart": The add to cart button on your stock products pages.
"visit_product": the URL product for the customer notification
"visit_product_text" : Returns the HTML content for the visit product text.
Most of the popular Shopify Liquid filters have been made available for you to use in the customer email template. If you find a filter is missing please contact support to see if it can be added.
If you're unfamiliar with Liquid templates take a look at Shopify's Liquid introduction to learn the basics.