Stok — Back in Stock & Restock Alerts App for Shopify

When a product sells out, the traffic does not stop. Those visitors already wanted the thing enough to find it, and they arrive at a dead end. Most stores respond by hiding the product or showing a greyed-out button, which converts the visit into nothing at all.

A Notify Me button changes the outcome twice over. It captures a buyer who is already committed, so the restock email lands on someone with proven intent rather than a cold list. And it turns your out-of-stock pages into a demand-forecasting tool — 60 people waiting on one size tells you more about what to reorder than any sales report, because it measures demand you could not fulfil.

That second effect is the one merchants underrate. The alerts recover revenue; the waitlist data stops you under-ordering the same product again.

Restock alerts are time-sensitive in a way most marketing is not. A limited restock can be gone in an hour, and an email sitting unopened until evening is a wasted notification.

Which channel wins depends entirely on your market. Email is the sensible default and costs nothing per send. SMS gets opened within minutes and suits high-value or genuinely scarce items where the message is worth $0.02. WhatsApp is the one most apps skip, and it is the difference between reaching and missing your customers in India, Brazil, Indonesia, the UAE and much of Southern Europe — markets where a marketing email is close to invisible.

Stok sends on all three from the $10 plan. If your customers live in a WhatsApp-first market, that single fact should probably decide your app choice.

A waitlist defers the sale. A preorder captures it.

If the restock is already confirmed — stock on the water, a production run booked — there is no reason to make the customer come back and buy again later. Preorders let them reserve now, with full or partial payment and an expected delivery date shown up front, so the sale is banked and the customer is not free to buy the same thing from a competitor in the meantime.

The practical rule: use a waitlist when the restock is uncertain, and a preorder when it is confirmed. Stok includes one preorder offer on the free plan, which is enough to test whether your customers will pay upfront before you commit to anything.

A restock alert written in English, sent to a customer who browsed your store in French, mostly reads as spam. Stok ships 29 languages and matches the customer's language automatically, with RTL support for Arabic and Hebrew, and you can override any individual string.

On the Pro plan you can also send from your own domain (alerts@yourbrand.com) rather than a shared sender. That matters more than it sounds: deliverability on shared sending domains is the usual reason restock emails land in spam, which is a particularly expensive place for a time-sensitive message to end up.

Install the app and the Notify Me widget appears automatically on out-of-stock products — no theme code, no snippet to paste. It works on product pages and collection pages.

Choose what the signup form collects: name, email, phone, WhatsApp, quantity, or a custom message. Customise the email, SMS and WhatsApp templates to match your brand, and send yourself a test before it goes anywhere near a customer.

Then decide how notifications fire — automatically the moment stock lands, in timed batches to avoid a stampede on limited restocks, or matched to the quantity actually available so you only alert as many people as you can serve. That last option is worth setting up properly; alerting 400 people about 30 units creates 370 disappointed customers.