Understanding First Paid, First Served

Learn all about the First Paid, First Served feature and how it affects inventory & cart settings.

What is First Paid, First Served?

First Paid, First Served is a feature that changes how your shop pulls inventory during a sale. With this feature enabled, inventory is not reserved once it goes into a customer's cart. Instead, the first person to pay for that item is the first person who will "win" it.

This is quite a bit different than traditional CommentSold selling, where the product is held for the first person to cart an item as long as they complete their purchase within an allotted timeframe. 

There are two exceptions to this:

  • If the customer clicks to pay with PayPal or Sezzle, the item will be held temporarily to allow for the shopper to checkout. The hold allows her to complete the payment process from Sezzle or PayPal and not have the items purchased out from under her while completing the transaction.
  • If an Admin adds an item to a customer’s cart, it will hold the item in the cart for the configured Cart Expiration time.

We highly recommend refraining from enabling and/or disabling this feature during high volume times for your shop. 

How Does it Work?

Let's use this product as an example and watch the inventory page to see how it works!

Screen Shot 2020-04-15 at 8.05.09 PM

Scenario A: The product is in stock, and your customer is paying with a card.

  1. Customer adds a product to cart

    1. In Stock is unchanged

    2. In Cart increases

    3. Sold is unchanged

  2. Customer clicks Pay with Card

  3. CommentSold checks to see if items are in stock and reserves them. At this point, in Stock is decremented.

  4. Purchase completes

    1. In Stock decreases
    2. In Cart decreases

    3. Sold increases

Item in cart:

Screen Shot 2020-04-15 at 8.10.25 PM

Item purchased:

Screen Shot 2020-04-15 at 8.14.23 PM


This process will vary slightly for customers who pay with PayPal or Sezzle. Once the customer clicks on PayPal or Sezzle as her payment method, CommentSold checks to see if items are in stock and reserves them momentarily at this point.


If the customer does not complete checkout during this time, the inventory will be returned to stock and available for the next person to purchase.

 Scenario B: The product is NOT in stock.
  1. Customer adds a product to cart

    1. In Stock is unchanged

    2. In Cart increases

    3. On Waitlist is unchanged

    4. Sold is unchanged

  2. Customer clicks Pay with Card (or Sezzle/PayPal)

  3. We check to see if the item is in stock. It is not. An error message is shown and the items are added to the waitlist 

  4. Purchase does not complete. Payment is not completed.

    1. In Stock is unchanged

    2. In Cart is decreased

    3. On Waitlist is increased

    4. Sold is unchanged


Customer Point of View for First Paid, First Sold

Let's take a look at what your customers will see when you have this feature enabled!

When a customer adds a product to their cart, they will see this message:

Screen Shot 2020-04-15 at 8.32.17 PM

If the product is in stock when they check out, they will see the normal "Thank you for your order!" banner.

If the product is not in stock, they will see this banner instead:

Screen Shot 2020-04-15 at 8.37.06 PM

Waitlists with First Paid, First Sold

Waitlists work differently with First Paid, First Served.

When a waitlisted item comes back in stock, we only process the products that have been pre-authorized. Items that are not waitlist authorized are not automatically added to carts, and your customers are not notified of an item being back in stock. You can use the Email Waitlist feature to have shoppers preauthorize the items if they want them, as well as to alert the customers when the items have come back in stock. Read more about this here.


That's all there is to it! Please chat us in support if you have technical questions about this feature!

Exceptions and Important Notes

With Shopify Sync enabled, turning on First Paid First Served may be very slow if many items are currently held in carts. Additionally, turning First Paid First Served on and off frequently may increase your likelihood of overselling.