A restock should be one of the easiest emails you ever send. The product is proven. The demand is real. The buyers have already told you they want it.
So why do most restock emails feel like a scramble? Why do they go to the entire list when only a slice of it cares? Why do they hit your top customers three times for the same SKU?
Because restocks usually happen on the operations team's schedule, not the marketing team's. The warehouse pings Slack at 2 PM. By 2:45, someone's writing a campaign. By 4, it's out the door. To everyone.
Let's talk about how to plan restocks like a campaign, not a fire drill.
The problem with blasting your whole list
A restock email is, by definition, a niche message. The audience for "the lavender candle is back" is small. It's the people who bought the lavender candle, the people who tried to buy it while it was out of stock, and a thin layer of customers who follow your candle launches in general.
That's maybe 8% of your active list. Possibly less.
When you send it to 100%, the other 92% see "Lavender Candle is Back!" and feel nothing. Worst case, they unsubscribe because you keep sending them messages about products they don't buy. Most case, they ignore it and your engagement metrics drift down a quarter of a percent.
Do that twice a month for a year and your sender reputation has quietly eroded. Not from one bad send. From two dozen mediocre ones.
Build the three segments you actually need
You don't need a perfect restock segmentation strategy. You need three segments, and you can build them in Klaviyo in about twenty minutes.
Segment 1: Past buyers of the specific SKU
Anyone who has purchased this exact product before. These are the people most likely to repurchase, especially for consumables, refills, or items that wear out.
In Klaviyo: "Placed Order" where item name contains [product name] over all time. Refine if you have multiple SKUs of the same product.
Segment 2: People who tried to buy it while it was out of stock
This is the slept-on segment. Klaviyo's "Back in Stock" signup data sits there, and most brands never use it for anything except the automated back-in-stock email. But these people raised their hand. They're warmer than warm.
If you don't have back-in-stock signup enabled on your product pages, fix that this week. It's a free segment-building machine.
Segment 3: Browsers in the last 30 days who didn't convert
People who viewed the product page recently but didn't buy. Klaviyo's "Viewed Product" event makes this easy. Cap it at 30 days so you're not emailing someone who looked once in March.
That's it. Three segments. Combine them with an OR condition and you have your restock audience.
Stop running the same play twice
Here's where most teams blow it. They send the restock announcement to the combined segment. Then two days later, they decide they want one more push, and they send the same email to the same segment.
The people who were going to buy already did. The people who didn't are now getting the second knock, and they've already decided no. You're not converting them. You're just reminding them you exist while they don't want anything from you.
If you want a second send, change the angle. The second email should be for people who opened the first but didn't click, or clicked but didn't buy. Different message. "Going fast" beats "still available." A real countdown beats a polite reminder.
And if you sold out again, send the sold-out email to the non-buyers. That builds future back-in-stock signups for the next round.
Time it to the buyer, not the warehouse
The warehouse tells you a product is back in stock at 11 AM on a Tuesday. You don't have to send the email at 11:15.
Restocks have a window. Open it when your buyers are actually checking email. Look at your "Viewed Product" event for that specific SKU and check what hours and days had the most views over the last six months. Send the restock email at the front of that window.
For most DTC brands selling to consumers, that's Tuesday through Thursday, between 9 AM and 11 AM in the buyer's timezone, or between 6 PM and 8 PM. Your data may say different. Trust your data.
The hour you pick can shift open rates noticeably. The day you pick can shift revenue per send a lot more.
Pre-write the templates so the scramble stops
The reason restock emails feel rushed is because nobody owns them until the warehouse says "go." Then a marketer scrambles to write something, the copy is generic, and the send is sloppy.
Fix this by pre-writing two templates per product line:
- The "back" template for the initial announcement. Subject line, body, image slot, CTA. Fill in the SKU and ship it.
- The "going fast" follow-up template for the second send if you decide to push.
Store them in Klaviyo as draft campaigns or in a shared doc your ops team can grab from. The marketer's job becomes "QA and schedule," not "write from scratch under pressure."
This is exactly the kind of work that gets messy when your campaign calendar lives in someone's head or in a spreadsheet nobody updates. A real calendar tool like Cadento lets you slot a restock campaign in the moment ops gives you the date, with the template pre-loaded and the segment already saved. The scramble disappears.
Track restock revenue separately
If you bury restock emails inside your regular campaign performance, you'll never know how well they actually work. Their open rates will look weird (high, because they go to engaged segments). Their unsubscribe rates will look great (low, because the audience is self-selected). Their revenue per send will be all over the map depending on price point.
Tag them. In Klaviyo, use a campaign tag like "restock" so you can filter and compare across the year. Look at revenue per send for restocks specifically. Look at the conversion rate of your back-in-stock signup segment versus your past-buyer segment. Find the SKUs where restock emails crush, and figure out what they have in common.
That data is what tells you which restocks deserve a second send and which ones don't.
The takeaway
Restock emails fail when they're treated as a notification. They work when they're treated as a campaign with a small, motivated audience.
Build three segments. Pre-write the templates. Time the send to the buyer. Track the revenue. Stop blasting the full list.
You'll send fewer restock emails to fewer people, and you'll make more money doing it. Your overall list will thank you by staying engaged for the campaigns that do go to everyone.