A shopper searches, finds the product, reads the description, decides, and then sees that it is out of stock. They leave. Three weeks later the delivery arrives and the product goes back on the shelf, and nobody tells them.
That is the most expensive kind of lost sale, because everything before the last step went right. The customer found you, wanted the thing, and was ready to pay. All that was missing was timing.
Back-in-stock alerts fix the timing. A shopper on an out of stock product leaves their email, and the moment the stock arrives in ERPNext they hear about it.
How it knows
This is the part that is easier for us than for a shop plugin working alone. A storefront only knows what it has been told about stock. ERPNext knows when the goods receipt was posted, which warehouse they went to, and how many there are.
A job runs daily, reads the current stock level for every item somebody is waiting on, and sends the notification when the number moves above zero. The alert is marked as sent so nobody is emailed twice for the same restock, and the waiting list for that product clears.
There is nothing for your team to do at any point. The warehouse receives stock the way it always has, and the people who wanted it find out.
Why it converts
The email arrives for a product the customer chose themselves, at the one moment it is available. They have already done the comparing. Compared with a newsletter, which interrupts somebody who was not thinking about you, this reaches somebody who was.
It also tells you something you otherwise have to guess at. A product with forty people waiting on it is a product you are underbuying, and that list is a demand signal your purchasing decisions can use. Most businesses discover their real backorder demand long after it would have been useful.
What it costs you to leave off
The arithmetic is unsentimental. Count the times something popular goes out of stock in a year, and multiply by the shoppers who reached the product page while it was unavailable. Those are sales where the hard part, finding you and choosing, was already done.
Recovering a fraction of them pays for a lot.
See pricing or talk to us about what you run out of.

