Variants & Addons
Configure product variants (required selections like size/color) and addons (optional extras like toppings) for flexible ordering.
Variants & Addons
Many products require customers to make choices before they can be added to the cart. Storefront handles this through two mechanisms: Variants (required selections) and Addons (optional extras).
Variants
A Variant defines a dimension of required customization. The customer must choose from the variant's options before adding the product to the cart.
Variant structure
Product "T-Shirt"
└── Variant "Size" (required, min: 1, max: 1)
├── Option "Small" — +$0
├── Option "Medium" — +$0
└── Option "Large" — +$2.00Variant attributes
| Field | Description |
|---|---|
| Name | The variant label (e.g., "Size", "Color") |
is_required | If true, the customer must select an option from this variant before adding the product to cart. |
is_multiselect | Controls how many options a customer may pick. Off (default): the customer chooses exactly one option (single-select, e.g. Size). On: the customer can tick multiple options (multi-select, e.g. Toppings to skip or Allergen flags). When multiselect is on, every selected option's additional cost is added to the product price. |
| Min / Max | Selection-count bounds — used together with is_multiselect to express "pick at least 2 / at most 4". With is_multiselect off these are typically left at 1/1. |
Adding variants to a product
Open the product in Storefront → Products.
Click the Variants tab.
Click Add Variant and enter the variant name (e.g., "Size").
Add options under the variant — each option has a Name, an optional Description, and an optional Additional Cost.
Toggle Is Required if the customer must select this before ordering.
Click Save.
When a customer selects a variant option, its additional cost is added to the product's base price. With is_multiselect enabled, every selected option contributes its additional cost — a Coffee product with a multiselect Add-ins variant where the customer ticks Vanilla syrup (+$0.50) and Oat milk (+$0.75) gets both added to the line price.
Addons
Addons are optional extras grouped into Addon Categories. Unlike variants, customers choose zero or more addons — there is no hard requirement to select one (unless is_required is set on the category).
Addon structure
Product "Burger"
└── Addon Category "Toppings" (max_selectable: 3, is_required: false)
├── Addon "Extra Cheese" — +$1.00
├── Addon "Bacon" — +$1.50
├── Addon "Avocado" — +$2.00
└── Addon "Jalapeños" — +$0.50Creating addon categories and addons
Addon categories are shared across a store — create them once and reuse them on multiple products.
Navigate to Storefront → Products and open a product.
Click the Addons tab.
Click Add Addon Category — choose an existing category or create a new one.
Set Max Selectable (how many addons from this group the customer can pick) and toggle Is Required if needed.
Within the addon category, click Add Addon and set the Name and Price.
Click Save.
Excluding addons per product
If an addon category has addons that should not apply to a specific product (e.g., a vegan burger should not offer "Bacon"), you can set Excluded Addons on the product-addon category link to hide specific addons for that product only.
Sale-Priced Addons
An addon can itself be on sale. Each addon has is_on_sale and sale_price fields — when is_on_sale is true, the cart applies the addon's sale_price instead of its price for the duration of the sale.
Cart Calculations
When a customer adds a product to the cart, the API calculates the line item total:
Line Item Total = (Base Price
+ Sum of selected variant additional costs
+ Sum of addon prices (sale_price if is_on_sale, otherwise price))
× QuantityExample:
- Burger base price: $10.00
- Selected variant "Large": +$0.00
- Selected addons: Extra Cheese ($1.00) + Bacon ($1.50)
- Quantity: 2
- Line item total: $25.00
The variant and addon selections are stored in the cart item and passed through to the Fleet-Ops order payload so the merchant knows exactly how to prepare each item.