When are Back in Stock emails sent, and why didn't my customers get one? (Essent Preorder Back in Stock app)
The Back in Stock email goes out automatically when a subscribed variant goes from out of stock (0 or less) to at or above the campaign's threshold. The threshold is set in the campaign's Notification settings tab under Once inventory is above or equal to. The default is 1. Emails usually go out within minutes of the restock.
Why an email didn't go out
- Stock didn't cross the threshold. The trigger is a real inventory increase. Switching a product to "Don't track inventory" doesn't trigger it.
- Wrong variant. Signups are per variant. Restocking size M doesn't notify people who asked for size L.
- Double opt-in. If GDPR confirmation is required, customers who didn't confirm are not emailed.
- Markets & locations. If you mapped markets to locations, a restock only notifies subscribers in the market that location serves.
- Plan limit. On the Free plan, emails pause after 300 notifications in a month until the count resets on the 1st, or until you upgrade.
- Another tool sends the email. If the campaign's Send emails through is Omnisend or Shopify Flow, the app doesn't send anything itself and the status columns show N/A.
- Spam folder. Ask the customer to check it.
Check each signup's status in Back in stock → Products & Notifications. Each subscriber gets one email per signup. To be notified again, they sign up again.
How to test
Set a variant to 0, sign up with your own email in an incognito window, then raise stock above the threshold and wait a few minutes. There is no "send test notification" button.
Full guide: Enable Back in Stock notifications in your store.