OptionfierOptionfier

Offer add-ons on a product

By the end you'll have a product page with a short list of extras under it: gift wrap, a battery pack, an extended warranty, whatever you sell alongside the main thing. A customer who ticks none of them buys the product exactly as before. A customer who ticks one or more gets the product plus each add-on as its own priced line in the cart, and Shopify tracks the add-on's stock like any other product.

There's no separate add-ons feature to turn on. It's a normal option set with one option set to Appears as: Bundle items, and the trick is in what happens when nothing is selected: Optionfier only turns the line into a bundle when there's at least one add-on to put in it. (This is for an ordinary product. A Build-a-Box has its own add-ons card.)

Build the option set

  1. Make sure the Optionfier block is on your product template. If it isn't, the theme guide takes two minutes.
  2. Open Optionfier from your Shopify admin and click New option set. Fill in Name.
  3. In the Product card, pick the product that gets the add-ons. That's the product your customer is actually buying, and it stays the parent of the cart line.
  4. In the Options card, click Add option, open Choice lists and pick Checkboxes, then Continue. Checkboxes are the natural fit because they start unticked, so "nothing selected" is a real state. A dropdown works too, but only with Include placeholder ticked in its settings, since that's what makes it start on nothing. Radio buttons, pill buttons and the product grid pre-select the first choice on their own, so skip those here.
  5. On the next step, "How do you want to add choices?", pick Pick products…. Shopify's picker opens. Select the variant for each add-on you want to offer. Every variant you pick becomes one checkbox with its product already linked, and the option's header reads "Appears as: Bundle items".
  6. Fill in Label. Something like "Add-ons" or "Extras" is what the customer sees on the cart and the order.
  7. Look at the choice rows. Each one shows Product, Qty and Price. Leave Price blank to charge the variant's own Shopify price, or type a number to charge something different when it's bought as an add-on here. Qty stays at 1 unless one tick should consume more than one unit.

Screenshot: an option's choice list with each choice row linked to a product

  1. Expand Option settings and tick Show component pricing. This is the whole point of an add-on list: the customer sees the price next to "Gift wrap" before deciding.
  2. Leave Required off. A required add-on isn't an add-on, and it takes away the plain-product path.
  3. Leave Charge for this product on (it's on by default). The main product has to keep its own price.
  4. Toggle Published in the Status card and hit Save.

Three settings that quietly break it

Each of these takes away the "nothing selected, normal product" path, so check them once and move on.

What the customer sees

The product page shows the add-ons as a list of checkboxes with a price next to each. Tick nothing and add to cart, and the product goes in as a plain line at its normal price. Tick one or two and add to cart, and the cart shows the product with each add-on indented beneath it, carrying its own name and price. Shopify decrements each add-on's stock at checkout, and refunds work per line in Shopify's own refund screen.

Screenshot: storefront cart drawer showing the parent product with its bundle components indented underneath, each with its own price

The two usual Bundle items caveats apply here too: your theme has to support Shopify's bundle format for the indented display, and it doesn't work on subscription products yet.

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