Back-in-stock alerts

Let shoppers join a waitlist for out-of-stock products and notify them automatically on restock.

When a product is out of stock, a shopper can join a waitlist. When you restock it, Enscale messages everyone waiting.

It's one of the highest-converting automations available, because the customer explicitly asked to be told.

How a shopper joins

Source	How
Storefront widget	A "notify me" form on the out-of-stock product page.
AI conversation	An agent offers to add them when they ask about a sold-out product.
Workflow	A flow adds them based on some other signal.

Each signup records the product, the variant if they picked one, when they signed up, and where it came from.

Variant matters. A signup for a specific variant is satisfied only when that variant restocks. A product-level signup is satisfied by any variant coming back.

How the notification fires

Shopify reports the restock

Enscale subscribes to inventory updates and sees the available count go positive.

Waiting contacts are found

Enscale looks up who's waiting on that product or variant.

The Back In Stock trigger fires

Your workflow runs for each waiting contact.

Their waitlist entry clears

The entry is removed. When a contact's last entry clears, the back-in-stock-waitlist tag comes off too.

Building the notification flow

Trigger: Back In Stock
  → Fetch Product
  → Format link  (product URL, UTM tagged, shortened)
  → Template Message: "{{product.title}} is back — {{link}}"

Two notes:

It must be a Template Message. No customer message opened a service window, so a free-form message won't deliver. See the service window rule.
Use Format link rather than pasting the product URL, so the resulting sale is attributable. See Revenue attribution.

Add urgency when stock is low

Trigger: Back In Stock
  → Fetch Product
  → Condition: available quantity < 10
      → Yes: "Back in stock — only a few left"
      → No:  "Back in stock"

Back-in-stock Subscribed fires when someone joins a waitlist, separately from the restock itself. Use it to confirm the signup — "we'll message you when it's back" — which reassures the shopper the form worked.

It's also a good moment to capture WhatsApp consent, since they've just asked you to message them.

The waitlist tag

Contacts on a waitlist carry the back-in-stock-waitlist tag. It's how Enscale finds them on restock, and it's removed automatically when their last entry clears.

Don't remove it by hand — the contact silently stops receiving alerts.

You can segment on it: everyone currently waiting on something is tags arrayContains back-in-stock-waitlist. See Segments.

Back-in-stock signups are a legitimate opt-in source, recorded as Storefront stock notify.

Treat the consent as scoped to what they asked for. Someone who signed up to hear about one product did not sign up for your weekly promotions — sending those to your waitlist is how you get opt-outs and quality-rating damage.

Troubleshooting

Problem	What to check
No alert on restock	Is inventory tracked for that product in Shopify? Untracked inventory sends no update.
Some contacts missed	Variant-specific signups only fire for that variant.
Alert fired but nothing sent	Contact lacks WhatsApp opt-in, or the flow used a free-form message.
Duplicate alerts	Check for more than one active workflow on the Back In Stock trigger.
Tag present but no entries	Contact support — the tag should clear with the last entry.