Back in Stock Emails and Texts: How to Turn a Waitlist Into Orders

Hayes Media, an eCommerce growth agency for DTC and Shopify brands, sends back in stock alerts in this order: one text at restock, one email, one reminder, then stop. A waitlist is a high intent list, because the shopper asked to be told. This guide covers how to capture the request on the product page, what to send at the moment of restock and in what order, how to handle a restock smaller than the waitlist, and how to read the result in gross profit instead of open rates.

Why is a back in stock request such a strong signal?

Because the shopper asked for it. Cart and browse triggers are inferred by you. A cart abandon means someone added a product and left, and you decide what that meant when you write the abandoned cart email. A browse event means someone looked at a page. A back in stock request is a different kind of signal. The shopper typed an email address or a phone number into a form for one product, in one variant, so they'd be told when it came back.

That hands you three facts at once. You know the exact product. You know the exact variant. And you know they wanted it at the price on the page, with no offer attached.

How do you capture the request on the product page?

Put the control exactly where the add to cart button was. When a variant sells out, replace the button in place with a plain "Notify me when it's back". Don't move it, don't hide it below the fold, and don't bury it in a tab.

Ask for one thing first. Open with a single field. Email is the safer default, because it costs next to nothing per send and isn't covered by the text consent rules below. Offer the phone number as a second, optional field with its own consent checkbox and its own disclosure text next to it.

Never treat a checkout phone number as SMS marketing consent. In the US, the FCC's consumer guide says commercial texts sent with an autodialer need the owner's prior written consent. We cover the consent rules and the real cost of an interrupting channel in our guide to SMS marketing for eCommerce.

Capture the variant, not just the product. A request for a medium isn't a request for an extra large. If your form records the product only, you'll notify people about a restock that doesn't include the size they asked for, and you'll train that list to ignore you.

Record the date of the request. You'll need it to send in order when stock is thin.

What should you send at restock, and in what order?

SMS first, email second, one reminder, then stop.

SMS goes first because a restock alert is time sensitive. A restock of a product that sold out is a race between the people on your waitlist. The text is one line, it arrives on a lock screen, and it does one job: get the person to the product page while stock is there.

Email goes second, a short gap later. Skip anyone who already ordered from the text. The email has room to make the full case for the product, and for people who never gave you a phone number, it's the only alert they get.

One reminder goes to the people who didn't order. After that, stop. The request is spent. A fourth message costs more and risks spam complaints from people who've already said no by not buying.

On timings, be careful with the numbers you read online. We don't publish a fixed gap between the text and the email, because the right gap depends on your restock size, your price point, and how fast the product cleared last time.

If you run Klaviyo, the platform handles the tracking and the hold. Klaviyo tracks a "Subscribed to Back in Stock" event on the profile when someone signs up, and the flow holds them at a delay step where, in Klaviyo's words, "Recipients that enter your flow will wait at this delay until their item of interest is restocked." Two settings there do the batching work. Klaviyo's help center describes minimum inventory rules as "how many items need to be restocked before you notify those who subscribed," and a "Customers to notify" setting that "determines how many customers are notified when an item is restocked."

Hayes Media works in Klaviyo for most accounts and has experience in most other email and SMS platforms, so a brand on another platform is still a fit. If your platform doesn't have these two controls, send in manual batches. If you're still building the core set, start with our guide to the Klaviyo flows every store needs and add this one on top.

What if the restock is smaller than the waitlist?

Send in the order the requests came in, and tell people that's what you're doing.

Take a made-up case: nine hundred requests and two hundred units. If you notify everyone at once, you create seven hundred disappointed people and one support queue. If you notify nobody until the full restock lands, you sit on inventory.

Send in batches, oldest request first. Use the platform controls for it. Set a minimum inventory rule so the flow doesn't fire on a restock of three units, and cap how many people each batch notifies.

Say the rule out loud in the message. One line is enough: "We're sending these in the order they were requested." That line does two things. It explains why someone's friend got the text first, and it tells the next batch that waiting has a payoff.

No fake scarcity. Don't write "only a few left" when four hundred units are sitting in the warehouse, and don't put a countdown on a restock that isn't going anywhere. The scarcity here is already real, so you don't need to invent it.

What should the email and the text actually say?

The text is short. Brand name so they know who's texting, the product, the variant they asked for, one link, and an opt out. Nothing else. Something shaped like this, written in your voice rather than copied: "[Brand]: the boots you asked about are back in a 9. Here: [link]. Reply STOP to opt out."

The email carries the case. Product name and image at the top. The variant they asked about, stated plainly, so nobody has to check. One button, repeated once further down. Then the things a buyer wants before spending money on a product that already sold out once: what it is, why it ran out, the return policy, and two or three reviews.

Don't attach a discount to either message. A code here hands margin to a buyer who'd already decided, and it gives your customers a reason to wait for the next sell out.

How do you measure a back in stock flow?

Four numbers, and none of them is an open rate.

Placed order rate per notified profile. Not per delivered message, and not per click. One profile can get a text, an email, and a reminder. Divide orders by the number of people you notified, and you have a rate you can compare against your other flows honestly.

Revenue at full margin. Track the revenue from these notifications separately from discounted revenue. A code can lift the conversion rate while gross profit per notified profile falls, so read the profit, not the rate.

Sell through. How fast did the restocked units clear, and how much of that came from notified profiles rather than from people who happened to be on the site? It's the number that tells you whether the waitlist is doing the work or the product is just selling itself.

Gross profit against the cost to send. SMS has a cost per message, so take the gross profit from notified buyers, subtract the send cost, and judge each channel on that. Over a longer run, the same logic rolls up into lifetime gross profit to CAC, which is the scoreboard we use across retention work. Our guide to eCommerce retention marketing explains how repeat orders raise what you can afford to pay for a new customer.

What does this look like in practice?

This example is illustrative. It uses made-up numbers to show the mechanism, not a client result.

A store has one thousand requests on a jacket, spread across five sizes. Six hundred gave an email address only. Four hundred gave both an email address and a consented phone number. A restock lands with three hundred units, weighted to the middle sizes.

First, filter to the sizes that actually came back. That drops the notify list from one thousand to six hundred and forty. The other three hundred and sixty stay on the waitlist and hear nothing, which is the point.

Second, batch. Three hundred units against six hundred and forty requests means you notify in waves, oldest request first, with the minimum inventory rule set high enough that a trickle restock doesn't fire the flow.

Third, order the channels. Wave one gets the text, then the email a short gap later to everyone who hasn't ordered, then one reminder to the people in that wave who didn't buy. When wave one has run and stock remains, wave two starts.

Then read it: orders divided by profiles notified, revenue at full margin, and how much of the three hundred units cleared from the waitlist rather than from general traffic.

When does this not apply?

If you never go out of stock, there's nothing to build. A store with deep inventory and no sell outs has no waitlist, and the effort belongs in your welcome and post purchase flows instead.

If you dropship, the restock signal is somebody else's. You often can't tell when stock returns, and the inventory feed you're reading may be stale. Notifying on a feed you don't control produces texts that send people to a sold out page.

If you make to order, the frame is wrong. Nothing comes back in stock, because nothing ran out. What you have is a production run, and that's a preorder or a launch announcement, which is a different message with a different promise.

If you sell one off or limited runs that never repeat, the same holds. Don't promise a restock that isn't coming. Collect the address for the next drop and say that's what you're doing.

And if your SMS list was built without proper consent, fix the consent before you build anything on top of it.

We build and run email, SMS, loyalty programs, and subscribe-and-save programs for eCommerce brands, and we run email and SMS as one engine. Book a discovery call and we'll audit your back in stock setup with you: how requests are captured on the product page, what fires at restock and in what order, and what the flow is returning in gross profit rather than in opens. No onboarding fees. No lock-in contracts. No junior marketers.

Sources

https://help.klaviyo.com/hc/en-us/articles/360051612551

https://help.klaviyo.com/hc/en-us/articles/115003872251

https://www.fcc.gov/consumers/guides/stop-unwanted-robocalls-and-texts