Change "Add to Cart" to "Pre-Order" on items that are selling while out of stock / Flex Theme

Store Design

Topic summary

A merchant using Shopify’s Flex theme wants to change the “Add to Cart” button to display “Pre-Order” or similar text when items are out of stock but set to continue selling. They operate a print-to-order business with some inventory on hand and need full payment upfront, making existing pre-order apps unsuitable.

Proposed Solutions:

  • Custom code modification: Edit theme files (likely main-product.liquid or product-form.liquid) to add conditional logic that checks inventory levels and “continue selling” settings, then displays appropriate button text
  • Pre-order apps: Multiple respondents suggest dedicated apps from the Shopify App Store, which offer features like custom button text, shipping notes, partial payments, and automated order management

Status: The discussion remains open with no final decision. The merchant must choose between implementing custom code changes (requiring developer skills) or adopting a pre-order app solution despite their initial reservations about existing apps.

Summarized with AI on November 2. AI used: claude-sonnet-4-5-20250929.
1

Hi Team, I sell a lot of items that are a Print to Order, however I keep SOME stock on hand. I would like to change my “Add to Cart” button to say “Pre-Order”, “Order In” (something along these lines) for when my inventory is set to continue selling on zero stock items. The Pre-Order apps don’t really suit my needs as I require payment at time of order to start making it. Hoping there may be a code somewhere I can change instead to show the buttons variation depending on if there is physical store, or it is print to order? (Currently out of sandbox Flex Theme) Thanks!

1 Like
2

Hi @Piperzqn

This requires a developer to add the pre-order button. It may not be compatible with your theme, but we can make it work—just let us know. Thanks!

Please don’t forget to Like and Mark Solution to the post that helped you. Thanks!

3

@Piperzqn You can definitely do this with custom code like in the replies mentioned, but I just want to highlight that it might be easier to manage through a preorder app from App Store. There are tons of options, and almost every app gives you more flexibility too like -

  1. Adding a note below the button to give your customers accurate information on shipping
  2. Collecting partial payments like a deposit upfront
  3. Setting up your shipping in Shopify admin so orders get fulfilled at the right time
  4. Managing preorders and sending timely updates on shipping.

We run a preorders and back in stock alerts named STOQ with all of this and more. And we work with many merchants similar to your situation that want to show special/pre-order info on specific products. More than happy to help you get set up and also get your feedback on it!

4

Hey,

Unfortunately, Shopify doesn’t have a built-in setting to automatically change the button text based on inventory levels. You’ll need to edit your theme code to add conditional logic in the product form template (typically main-product.liquid or product-form.liquid in Flex theme). The code checks if inventory is zero and “Continue selling when out of stock” is enabled, then displays “Pre-Order” instead of “Add to Cart.”

Also, K1 PreOrder can automate that (I’m the founder of K1 PreOrder), replacing the button automatically with customizable text and adding pre-order badges based on inventory-based display modes (Always / Out of stock / Below threshold) without code changes. If this is relevant, you can check K1 PreOrder app in Shopify Store.

Happy to help with the liquid code if needed.

Best regards,
Yauheni