Introduction
Managing pre-order buying limits helps you prevent overselling and share limited stock fairly. This guide explains how to set a total sales cap per variant in the Notify Me app for Shopify, how the limit is counted, and what happens once it is reached. You can set limits per variant (for example, per size or color) or for the whole product.
Before you start
Pre-order buying limits are available on higher subscription plans. Make sure your plan supports per-variant limits before you begin.
Limits are enforced by a checkout rule called Notify Me - Preorder Max Quantity Validation. Keep this rule turned on — disabling it will stop limits from working correctly.
What are pre-order buying limits?
A pre-order buying limit is the maximum number of units that can be pre-ordered for a product or a specific variant. It works as a total cap: once pre-orders reach the limit, Notify Me automatically marks the product or variant as sold out and stops further pre-orders.
Set a pre-order limit
In your Shopify admin, go to Apps → Notify Me, then select PreOrder from the left-hand menu.
Open the pre-order offer that covers the products you want to limit.
Scroll to the Maximum sales limit section and click Add limit.
In the Add maximum sales limit window, find each product or variant and enter a value in the Total Limit column — this is the maximum number of pre-orders allowed for that variant.
Click Save.
The same window also has a Max Cart Quantity column, which limits how many units a customer can buy in a single order. To use it, see Setting maximum purchase limits per order (Max quantity per cart).
How the limit is counted
This limit applies only to pre-orders — the units customers reserve through the Notify Me pre-order button while a product is on pre-order. Regular in-stock purchases through Shopify's standard Add to Cart button are counted and fulfilled as usual; they just don't count toward this pre-order cap.
The Total Limit is a running total, counted from the moment you first set it — not an amount added on top of past pre-orders.
Changing the limit does not reset this count. Pre-orders already placed still count toward the new limit. For example, if you set a limit of 5 and have already sold 3, changing the limit to 10 lets 7 more be pre-ordered (10 in total) — not 10 more.
Limits work independently of your actual inventory levels. They keep applying even when stock reaches zero.
What happens when the limit is reached
When pre-orders reach the limit, Notify Me marks the variant sold out automatically: it switches off that variant's "Continue selling when out of stock" setting in Shopify and hides the pre-order button.
To sell more, start a new round. Turn "Continue selling when out of stock" back on for that variant in Shopify (Products → the variant → Inventory). Notify Me re-adds it to pre-order automatically — you don't need to re-create the offer — and the count starts fresh from zero. Pre-orders from the previous round don't carry over.
Editing the limit never resets the count. The count only starts over when a new round begins.
Setting the limit at or below what's already been pre-ordered marks the variant sold out right away.
The error message a customer sees when they exceed the limit is not currently customizable.
Troubleshooting
"I increased the limit but the product sold out earlier than I expected." The limit is a running total from when it was set, and editing it does not reset the count. Pre-orders placed before your change still count toward the new limit. To start a clean count, open a new round (see above).
"The pre-order button disappeared." The variant most likely reached its limit and was marked sold out. Turn "Continue selling when out of stock" back on to re-open pre-orders.
"The limit is not being enforced at checkout." Check that the Notify Me - Preorder Max Quantity Validation checkout rule is turned on.
Plan-specific access
Advanced options such as per-variant limits may require a higher-tier subscription plan. Make sure your plan supports these features before configuring them.
Summary
Pre-order limits help ensure fair access to limited products and prevent overselling. The Total Limit is a running total from when you set it — changing the number does not reset it, and the count only starts over when you open a new round after the limit is reached. To cap units per order, use the Max Cart Quantity column in the same window.