I found a guide on the forum to add a back order button for items that are out of stock - the add to cart button changes to back order - this works very well however I get “Required parameter missing or invalid: items”
I dont want to have every product set “continue selling when out of stock” as the customer doesnt know it might not ship straight away. we have over 4000 products on our site so backorder will work very well.
The guide I followed is here :
Welcome to shopify community.
Can you share the code you added pls? Which theme are you using?
we have the venture theme and the code for the snippet is :
{% if product.available %}
Add to cart {% else %} Backorder (Usually ships within 48 hours) {% endif %}and then added in to the code on page is
{% render ‘backorder-button’ %}
Actually liquid theme
OK, Can you explain more detail to me when and where the error “Required parameter missing or invalid: items” shows
https://kartingcentre.com.au/collections/chassis-components-1/products/otk-engine-stop-bolt
as you click on the now back order button - it pops up with the error immediately and doesnt add anything to the cart
OK, Thank you. Since it is out of stock. So it should not add to cart. What behavior you expect after click the back order button?
do you just expect to remove the error, right?
really want an option for someone to have the ability to still order the product even though its sold out - however dont want to set the product as sellable if its sold out as it wont give a warning that its on back order
looking at the comments from the first link I shared it seems entirely possible ?
I think it is possible. Replace your current code with below cope snippet.
Feel free to reach out if you need any further assistance
sadly same issue with missing parameter
I did found the item id is missing if your product is out of stock.
So I need a further investigation on your theme and I have sent you a DM.
Do you allow sell product that out of stock?
Can you check if it selected?
if not, try selected it and retry the back order to see if it works.
Hey Peter!
Were you still having issues with this? Just wanted to suggest considering using an app for handling back-order products. We just launched one called Early Bird which makes setting up back-orders for your entire catalog super easy.
It also means no theme modifications or liquid code (one-click setup, removed completely on uninstall).
You can choose to activate back-orders for your entire catalog (even 4000 products!), or only for specific products you choose, and it will show clear messaging/labels that it’s a back-order once the stock reaches 0. And you can of course edit this messaging/styles as needed.
Feel free to check it out on our Free plan to see if it works for you! I’d be happy to help get you set up too if you have any questions or issues.
Here’s an example product with some of the different options we offer (password is “demo”). Hope it helps!
Hey,
The error occurs because the backorder button isn’t properly submitting product data to Shopify’s cart API. To fix this, go to Online Store → Themes → Actions → Edit code, then locate your product form template (usually sections/product-template.liquid or snippets/product-form.liquid). Ensure the backorder button uses the same form structure as your “Add to cart” button, passing the correct variant ID and quantity parameters.
Alternatively, an app like K1 PreOrder (I’m the founder) automates this—handling button replacement, inventory logic, and CSWOOS settings with flexible display modes like Always / Out of stock / Below threshold. Here’s the K1 PreOrder listing if relevant.
Happy to help with theme customization if needed.
Best regards,
Yauheni
