Product ID based custom fields in product blocks

Custom field based product personalisation is an optional extension to the Product selector and Specified products blocks.

It lets you use a specialised List of product IDs custom field to populate products dynamically for each recipient.

For example, you could use custom fields to display:

• Wishlists or favourites
• Recently viewed products
• Recommended products
• Loyalty rewards

This means you can create a single product block that displays different products depending on the data associated with each recipient.

Setting up custom field personalisation

Once the setting is enabled for the account, the UI will change to a new format (as shown below). All the existing block settings on templates will remain unaffected. 

There are three steps to configuring the block.

1. Select a store (Product selector only)

If you're using the Product selector, you must first select a store, then choose the custom field.

All products displayed in the block, including products populated from the custom field, will be based on the selected store.

Specified products doesn't have a store selection option.

2. Choose a custom field

Open the dropdown and choose one of the following:

• None to use the block as normal. It will display the products you've selected.
• A List of product IDs custom field to personalise the products for each recipient.

Only custom fields of this type appear in the dropdown.

3. Choose fallback products

If you've selected a custom field, the products you manually select in the block act as a fallback.

Fallback products are used to fill any remaining product slots when:

• A recipient has fewer products in their custom field than the block has available slots, including no products at all.
• A product in the custom field is no longer active or is out of stock, depending on your campaign's product filters.

If you've selected None as the custom field, your manually selected products will display as normal, rather than acting as a fallback.

How products are selected at send time

When the email is sent, the platform looks up the product IDs in the selected custom field for each recipient.

Products from the custom field are displayed first. If there aren't enough valid products to fill the block, the platform uses your manually selected fallback products to fill the remaining slots, following their priority order.

Example: Displaying recently viewed products

Imagine you've configured a block to display four products using a recipient's Recently Viewed Products custom field.

• Recipient A has four valid products in their custom field. All four are displayed.
• Recipient B has two valid products. The remaining two slots are filled using your fallback products.
• Recipient C has no valid products. All four slots are filled using your fallback products.
• Recipient D has no valid products and no fallback products have been selected. The email will still send, but the product block won't be rendered.

Limits and considerations

Keep the following in mind when using custom field personalisation:

• Product limit: Each block supports up to 12 products.
• Custom field type limit: You must use a List of product IDs custom field.
• Multiple blocks: You can use multiple custom field blocks in the same template, with each block referencing a different custom field.
• Campaign types: Custom field personalisation works in both broadcast and automation campaigns.
• Preview behaviour: When you first add the block to a template, the visual editor displays a placeholder. Once you save the template, the preview displays real product data from a sample profile.

See also: Product recommendation block