Preorders and waitlists: how to capture demand when a product sells out

When a product sells out, don't take the page down: replace the buy button with a way to keep the buyer. A waitlist (a free “notify me when back in stock” form) collects emails with no payment and fits when you don't know when stock returns. A backorder takes a normal order when a restock is confirmed and close. A preorder takes a firm order, paid now or later, when you know the stock is coming. Then send the back-in-stock email the moment the product is available again, while people still want it.

Without that, “Out of stock” usually means a lost customer. Someone came for that exact product, found no way to buy it and left, most likely for a competitor. With a waitlist or a preorder you turn that moment into a list of buyers with an email, the exact variant they want and clear intent, counted before you even place the order with your supplier. Below: how the three options differ, how to take payment for preorders, what the law expects on delivery dates and refunds, and how to run the restock email so the list actually turns into sales.

Preorder, backorder or waitlist: which one fits

People mix them up, but each one solves a different situation.

• A waitlist (the “notify me when back in stock” button) asks for no money. The person leaves an email and gets a message when the product is available again. It fits when you don't have a firm restock date, when you're testing whether a product is worth reordering, or when you simply don't want to lose the contact.
• A backorder is a normal order for an item you usually stock but have temporarily run out of. The customer buys now and you ship when the delivery from your supplier arrives. It only makes sense when the restock is confirmed and close.
• A preorder is an order for something that isn't available yet: a new product, a new batch, a launch. The customer commits now and pays in full, pays a deposit, or pays when it ships. It fits when you're confident the stock is coming and you want to fund production or measure real demand before launch.

Simple rule: if you control when delivery happens, take orders (backorder or preorder). If you don't, use a free waitlist and convert later. Many shops use all three across the catalogue and move between them: a waitlist builds interest, then the people on it get first access when the preorder opens.

Keep the sold-out page live

The product page that just sold out already has visitors and, often, a place in Google. Deleting it or redirecting it to the homepage throws both away.

• Leave the page up and label it clearly: “Sold out”, “Available on backorder” or “Preorder: ships in [month]”.
• Put the “notify me” button exactly where the buy button would have been, not buried at the bottom of the page.
• Update the availability in your product structured data. Google's merchant listing documentation supports values such as InStock, OutOfStock, BackOrder, PreOrder, PreSale and SoldOut, so search results can match what the page says.
• Show a few similar products under the form for people who won't wait.
• If the product is discontinued for good, say so (Google also supports a Discontinued value). Collecting emails for something that won't come back burns the trust you're trying to build.

What to collect, and how, so you don't scare buyers off

Ask for the minimum. For a waitlist, the email address is enough, plus the exact variant (size, colour, model) already selected on the page, so you don't tell someone who wanted a medium that the large is back. Every extra field cuts into how many people complete the form. If you also want to send alerts by SMS or WhatsApp, ask for the number separately and mark it optional.

• Confirm on the spot with a clear message: “You'll be the first to know when it's back.”
• Send a confirmation email so the person knows the signup worked. If you ask them to click a link in it to confirm (double opt-in), it also keeps mistyped or fake addresses off the list.
• Be clear about what they're signing up for. Someone who asked for a restock alert asked for that message; adding them to your newsletter needs a separate checkbox they tick themselves. More in our guide to GDPR for small websites.

For a preorder you're in payment territory: you need billing and shipping details, a payment processor (Stripe, for example), and a page that clearly states what they're buying, what it costs and when they'll receive it.

Taking payment for preorders: now, a deposit, or later

How you charge decides how much you have to give back if the supplier lets you down.

The later you charge, the less you refund when things slip, but the more orders fall through when the card is finally charged or the link goes unanswered. Pick the model that matches how sure you are of the delivery date.

One technical trap: a card “hold” (authorise now, capture later) doesn't last long enough for most preorders. Stripe's documentation says an authorisation for an online card payment is usually valid for 7 days, after which the funds are released. For anything that ships later, save the payment method at checkout and charge it when you dispatch, and tell the customer at checkout exactly when they'll be charged.

On Shopify, preorders run through a pre-order app from the Shopify App Store rather than a built-in switch; Shopify's help centre says these can take full, partial or no payment when the order is placed. If you're setting up card payments from scratch, see our guide to online payments on your website.

Whatever the model, cap preorders at the quantity you can actually deliver. When the cap is reached, switch the button back to a waitlist for the next batch instead of selling stock you won't have.

Delivery dates, cancellations and the law

This is where trust is won or lost. Someone who preorders hands you money, or at least a commitment, for something they can't hold yet, and consumer law in the EU, UK and US protects them.

• EU delivery: unless you agree otherwise, you must deliver without undue delay and no later than 30 days after the contract is concluded. If you're late, the customer can give you an extra, reasonable deadline and, if you miss that too, cancel and get their money back. That's why a preorder needs a delivery estimate the customer sees and accepts at checkout.
• EU right of withdrawal: online buyers have 14 days to withdraw without giving a reason, counted from delivery of the goods, not from the day they paid. You must refund within 14 days of being notified, though you can hold the refund until you get the goods back or proof that they've been sent. Don't hide it; put it in plain view. It reads as seriousness, not weakness.
• UK: the Consumer Rights Act 2015 sets the same default: delivery without undue delay and within 30 days, unless you agree another time. Under the Consumer Contracts Regulations 2013, the 14-day cancellation period runs from the day the goods reach the customer.
• US: the FTC's Mail, Internet, or Telephone Order Merchandise Rule expects you to have a reasonable basis for any shipping time you state, and to ship within 30 days if you state none. If you can't ship on time, you must ask the buyer to agree to the delay and give them the option to cancel for a full, prompt refund.

In practice:

• Give an estimated delivery date you can actually meet, not an optimistic guess. “Estimated delivery: end of October” beats a promise you'll miss.
• Put your preorder cancellation and refund policy on the product page and in the confirmation email, not only in the terms.
• If a delay happens, write to customers before they ask, with the new date and the option to cancel. A proactive “it's running two weeks late, here's why” email keeps people on board.

This is a practical summary, not legal advice. Check the rules for each country you sell to.

The restock moment: from list to sale

The list is worth nothing if the back-in-stock email goes out late or badly. A few rules that matter:

• Send the alert the moment the product is available again, not three days later. Intent fades fast.
• Make the subject line say exactly what it is, for example “Back in stock: [product name]”, and link straight to the right variant, not the homepage.
• Don't fire alerts for a single returned item. Set a minimum quantity before the alert goes out, so people don't click through only to find it gone again.
• If you have fewer units than people on the list, notify in batches, earliest signups first, or say openly how many are available.
• Give the waitlist a real head start: let them buy a few hours before the general public. It becomes a privilege, not just a notice. If you can, hold stock for them for a short window.
• Send one reminder at most to those who didn't buy, and only while stock lasts. Remove buyers from the flow straight away, and make sure nobody gets an abandoned-cart email and a restock alert for the same item.
• If it sells out again, tell the people who missed out and offer the next batch as a preorder or a close alternative.

What to measure

• Signups per product and variant: the demand you used to lose without seeing it.
• Opens, clicks and purchases from each restock alert.
• Unsubscribes after alerts, a sign the list has gone cold or you're sending too much.
• Preorder cancellations and refund requests, an early warning that your delivery estimates are off.

If a product sells out often, that's a business signal: demand outstrips supply. Use the numbers from your list to negotiate with the supplier or justify a bigger batch next time.

How to set this up on your site without overcomplicating it

You don't need an expensive platform. On most shops, a “notify me” button plus a simple email integration covers the waitlist. Preorders also need a correctly configured payment processor and clear product pages.

• Shopify: with inventory tracking turned on, the Inventory section of a product or variant has a “Continue selling when out of stock” option, which lets customers keep ordering, backorder-style. Preorders need a pre-order app, and back-in-stock alerts are usually added the same way.
• WooCommerce: store-wide stock options live under WooCommerce > Settings > Products > Inventory. Leave “Out of stock visibility” (the box that hides out-of-stock items from the catalogue) unticked if you want people to find the page and join the waitlist. Backorders are switched on per product, in the product's own inventory settings; back-in-stock alerts and preorders come from extensions.
• Custom-built site: a short form that saves the email, product and variant, an automatic confirmation email, and a trigger that sends the alert when the stock is updated.

At MPO Web Studio, a small web studio from Cluj-Napoca, we build exactly this kind of flow on sites made for local businesses: a waitlist button, an automatic confirmation email, a restock notification and, where it makes sense, a paid preorder through Stripe. We work remotely across Romania, with transparent pricing and a free pre-built demo, so you can see the mechanism before you decide.

If you have products that sell out and you lose customers with every wave, message us on WhatsApp. We'll tell you honestly what can be done on your current site and what it costs.