The back in stock flow for Shopify stores
A back in stock flow for Shopify stores: how to collect requests, when to send, full copy, and setup notes for Klaviyo and Omnisend.
The flow at a glance
A back in stock request is one of the strongest buying signals a shopper can give. They wanted it enough to ask. The flow just needs to tell them fast.
- 1Email 1: It's back
- 2Email 2: Reminder
Who waits, and what they wait for
Nobody in this flow is waiting for a date. They are waiting for one variant of one product. A shopper who asked about the medium in green should hear nothing when the large in blue comes back. Check that your form records the variant, not just the product, before you build anything else.
If a restock is small, the people who asked first should hear first. Sending to the whole waiting list at once and selling out in minutes turns your most eager customers into your most disappointed ones.
Email 1: It's back
Subject: Product is back
Preview: You asked us to tell you
The product image, the name, the size or variant they asked for, one button. If stock is limited, say how limited.
Email 2: Reminder
Subject: Still want product?
Preview: It is going quickly
Short. Only send if it is still in stock. One review about the product.
Setup notes
Klaviyo: enable back in stock on your product pages, then build a flow triggered by "Subscribed to Back in Stock". Klaviyo checks inventory and sends when the variant is available again.
Omnisend: use its back in stock feature and workflow if enabled for your account, or a dedicated back in stock app that integrates with it.
The reminder cannot see your stock
The table above says to send the reminder only if the product is still in stock. In Klaviyo that check is on you. Once the first email has gone, Klaviyo does not look at inventory again before the next one, so a reminder can go out for something that has already sold out. source, checked 25 September 2026
For a product that sells out fast, the honest options are a single email with no reminder, or a reminder written so it still reads well if the item has gone: point to the closest alternative and offer to add them to the list again.
What to measure
- Conversion rate from request to order
- Time from restock to sell-out
- Requests per product, to plan how much to reorder
Reading the request list before you reorder
The requests are a demand forecast that customers filled in for you. Sort them by variant, not by product: a size that nobody asks for is a size you can order less of next time. Compare the requests with the orders the flow produced, and you learn how many people who ask actually buy, which tells you how much of the next restock is already spoken for.
Questions people ask
Should I email everyone about a restock, or only people who asked?
Email the people who asked first, through this flow. If the product is popular, a campaign to the wider list a day later works well, and the calendar agent can plan it.
What if stock is limited?
Say so honestly, and consider sending in batches so the first people to ask get the first chance.
Why is my back in stock waiting list empty?
In Klaviyo, check the status of the email after the back in stock delay. If it is in draft, nobody is added to the waiting list. source, checked 25 September 2026
Can I add past customers to a back in stock flow?
It rarely helps. People enter this flow by asking for a specific item, and adding past profiles usually brings nobody new in. source, checked 25 September 2026
How Tilly uses it
Restocks are added to your email calendar as store events, so a campaign to the wider list can follow the flow.
Mistakes that cost this flow
- Announcing the restock to the whole list before the people who asked have had their chance.
- Showing the product but not the variant they wanted, so they have to find it again.
- Putting a discount on something people were already queuing for.
- Saying stock is limited when it is not. The next time you say it, nobody believes you.
See this on your own store
Paste your store URL. The first pass takes about a minute and needs no account. Save a card (nothing is charged) and Tilly reads the whole store and works out who buys from you.