Pre-order for out-of-stock Product Variants

Shopify Discussion
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Topic summary

A merchant needs a solution where individual product variants automatically switch to pre-order mode when out of stock, without affecting other in-stock variants of the same product. Previously tested apps incorrectly treated the entire product as pre-order when just one variant sold out.

Solutions offered:

  • Manual theme customization: Enable “Continue selling when out of stock” in Shopify admin for each variant, then add custom Liquid/JavaScript code to the theme that dynamically changes the “Add to Cart” button text to “Pre-Order” based on the selected variant’s inventory level.

  • Dedicated apps: Two pre-order app providers (STOQ and Early Bird) confirmed their solutions handle pre-orders at the variant level, allowing specific variants to switch to pre-order independently. Both apps can automatically toggle pre-order status when variants reach zero inventory and offer setup assistance.

The discussion remains open with multiple viable options presented but no final decision indicated.

Summarized with AI on October 29. AI used: claude-sonnet-4-5-20250929.
1

Let’s say you have a product with 2 variants. When one variant reaches zero stock, I need it to continue to sell but switch to PreOrder on its own. It shouldn’t affect the other variant.
Do you have a solution to this? I tested some apps, but they treated the whole product as PreOrder when one of the variants’ stock reached zero.

2

Hi @Paul_magdas ,

That is a creative approach to continue the product sales. Here are some steps that can solve.

  1. Set the product variants to continue selling when out of stock
    In your Shopify Admin:
  • Go to Products > [Your Product]
  • For each variant, click Edit
  • Check “Continue selling when out of stock”

This ensures the variant can be purchased even if inventory is 0.

  1. Use custom Liquid in your theme to show “Pre-Order” only when the selected variant is out of stock
    Modify your theme’s product-form.liquid or main-product.liquid (depending on your theme structure).

Here’s a basic snippet to guide you:

This script updates the Add to Cart button text based on the selected variant’s stock level.

Hope this will help. Let me know if you need more help.

Regards,

2 Likes
3

Hey, @Paul_magdas . We have this on STOQ - our app for preorders & back in stock alerts. Everything in STOQ is defined at the variant level - i.e. you can choose to say that only one variant should ever turn to preorder and the other one should not.

We also have another feature where you can set preorder/backorder for all products on your store, and exclude specific variants from ever being picked up to turn into preorder. Let me know if you have any questions or need help - happy to walk you through it!

4

Hi @Paul_magdas , Josiah from Early Bird here. :waving_hand:t2: We’re one of the few Built-for-Shopify pre-order apps (Early Bird) that lets you run pre-order campaigns and capture coming soon/back-in-stock emails - all at a variant level. It’ll auto toggle to capture pre-orders for you when a specific variant is sold out (while your in-stock ones will sell as normal).

I see Sandy from Stoq has already offered to walk you through the setup - we’ll be here to guide you through the end-to-end process as well if you’re looking for different pre-order app options. :slightly_smiling_face:

Josiah

5

Hey,

First, Shopify’s native approach lets you enable Continue selling when out of stock for each variant individually (Products → select product → click on a specific variant → Inventory section → check Continue selling when out of stock). When one variant hits zero, that variant alone will accept orders while others remain unaffected. Here’s Shopify’s inventory guide.

The trade-off is that the button text stays “Add to cart” regardless of stock levels—customers won’t see a visual pre-order indicator unless you customize your theme.

Alternately, an app like K1 PreOrder can automate that (I’m the founder of K1 PreOrder), switching the button to “Pre-order” per variant when inventory reaches zero, with automatic inventory setting management and customizable button text and badges (it doesn’t affect other product variants). If this is relevant, here’s the K1 PreOrder listing.

Happy to help with the theme customization if you need it.

Best regards,
Yauheni