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BundlePilot

How to let shoppers pick a variant for each item in a Shopify bundle

When every item comes in sizes, a variant per combination gets out of hand. Give each item its own slot and its own variant instead.

Potted plants of different sizes in different pots on a wooden shelf
Photo via Burst, Shopify’s free stock library

Updated . A 6-minute read by the BundlePilot team at Boldnsmart.

Short answerGive each item in the bundle its own slot and let the shopper choose that slot’s variant on the product page. In BundlePilot you pick one main product, whose variants become the size selector, and add complimentary products, each with its own variants or a choice between products. The order then records each pick, and each item’s inventory goes down on its own.

BundlePilot is a Shopify app built for this. See it on the Shopify App Store.

Why one bundle product with fixed variants breaks down

The quick way to make a bundle in Shopify is a single product whose variants describe every combination. That works for one or two options and stops working the moment each item has choices of its own.

  • Every option multiplies the list. Three tree sizes, three pots and two cards make 3 × 3 × 2 = 18 variants to create, name, price and photograph; a fourth pot makes 24.
  • Stock drifts. The bundle’s variants keep their own inventory, so you end up adjusting the tree, the pot and the bundle by hand.
  • Shoppers scroll a long dropdown instead of making three simple choices.
Before18 variantsIllustrationOne for every combination.
Illustration of a Shopify product page whose one Variant dropdown lists every tree size, pot and card combination
After3 picksDemo store screenshotEach keeps its own price and stock.
A real BundlePilot product page: one selector for the lemon tree size, one for the pot and one for the card, the pot and the card included

What “a variant per slot” means

A slot is one position in the bundle: the tree, the pot, the card. Each slot shows its own choices, the shopper picks one in each, and the bundle price is worked out from those picks. Two kinds of slot cover most bundles:

  • One product’s variants. The card slot offers the greeting card’s own variants: classic or premium.
  • A choice between products. The pot slot offers three different pot products: a nursery pot, a glazed pot and a giant pail.

Research backs letting shoppers choose. In three experiments, two further studies and a meta-analysis, Kobuszewki Volles and co-authors found that “incorporating bundles into the assortment and having consumers select these bundles increases overall purchases” (Journal of Retailing and Consumer Services, 2024). Fixed bundles carry a warning: bundle promotions were found “far more effective at inducing switching than at boosting category sales” (Foubert and Gijsbrechts, Journal of Marketing Research). Both studied grocery products, not a Shopify app.

How to set it up in BundlePilot

  1. Install BundlePilot

    Install it from the Shopify App Store. The setup guide on Boldnsmart walks through the install and the theme editor.

  2. Create the bundle and pick the main product

    Give the bundle a title, such as “Lemon tree gift bundle”, and choose one main product. Its own Shopify variants become the size selector shoppers see first. BundlePilot creates the bundle’s product in your store and publishes it to your Online Store.

  3. Add complimentary products

    Add each extra item as a complimentary product. For each one, choose whether the slot offers one product’s variants (classic or premium card) or a choice between products (a nursery pot, a glazed pot or a giant pail).

  4. Set what each option costs

    Leave standard options included at $0 and add a dollar surcharge to premium ones, for example +$6 for the glazed pot. The product page shows that surcharge next to the option.

  5. Switch it on and test it like a shopper

    Switch on the Bundle Builder block and the cart lines embed as in the setup guide on Boldnsmart. Then pick a different variant in each slot, place a test order and check that each item’s inventory went down.

Ready to give each item its own size?

Watch shoppers pick sizes: install BundlePilot from the Shopify App Store

Common snags

Add to cart says Sold out

One of the bundle’s parts is out of stock. BundlePilot switches the button to Sold out so a shopper can’t order a bundle you can’t pack. Restock the part, or remove that option from the slot.

The builder or the cart line is missing

Open the Setup page in BundlePilot: it checks your live theme and points to the missing step. The setup guide on Boldnsmart shows each one.

More bundle guides