Add line items

To add items to a customer's cart, use the create_line_item form tag.

At a minimum, each line item must include the ID of the variant or extra being added.

Basic usage

{% for variant in product.variants %}
  {% form "create_line_item" %}
    <input type="hidden" name="items[][variant_id]" value="{{ variant.id }}" />

    <input type="submit" value="Add to cart" />
  {% endform %}
{% endfor %}

Line item properties

Additional fields can be included depending on the type of product being booked.

Quantity

Specify the number of units to add to the cart.

<input
  type="hidden"
  name="items[][quantity]"
  value="2"
/>

If omitted, a quantity of 1 is used.

Modifier selections

If a variant or extra includes pre-checkout modifier groups, the selected modifiers must be submitted with the form.

<input
  type="hidden"
  name="items[][modifier_ids][]"
  value="<modifier_id>"
/>

Adult count

Per unit variants support occupancy-based pricing.

Specify the number of adults using:

<input
  type="hidden"
  name="items[][adult_count]"
  value="2"
/>

If omitted, the variant's maximum occupancy is used.

Experience slot

Experience variants require a slot ID to book a specific date or time.

<input
  type="hidden"
  name="items[][experience_slot_id]"
  value="{{ experience_slot.id }}"
/>

Accommodation dates

Accommodation variants require both a check-in and check-out date.

Dates must use the format YYYY-MM-DD.

<input
  type="hidden"
  name="items[][start_on]"
  value="2026-07-15"
/>

<input
  type="hidden"
  name="items[][end_on]"
  value="2026-07-18"
/>

Clear the cart first

To remove all existing cart items before adding the new line items, include the clear_cart field.

<input type="hidden" name="clear_cart" />

This is useful when building booking flows that should only contain a single booking at a time.

Developer considerations

When adding line items:

• Always include a variant_id (or extra ID).
• Include quantity when adding more than one item.
• Include all required modifier selections for variants and extras.
• Specify adult_count for occupancy-based pricing where appropriate.
• Experience variants must include an experience_slot_id.
• Accommodation variants must include both start_on and end_on.
• Use clear_cart when the booking flow should replace any existing cart contents.