Recipe: low stock alert to Slack

Goal: a Slack message when the available quantity of an item at a location drops to 5 or below.

Template: Low stock alert (category Inventory). Steps: 1. Needs: access to inventory, and a Slack incoming webhook URL.

Create it

Create a Slack incoming webhook for the channel. Open Secrets, select Create secret, name it SLACK_WEBHOOK_URL and paste the URL as the value. See Secrets.
Open Workflows, select Browse templates, search for low stock and select Use template on Low stock alert.

How it is built

Part	Setting
Trigger	Inventory quantity changed
Trigger filter	`event.payload.available` is at most `5`
Send Slack message	Webhook URL `{{ secrets.SLACK_WEBHOOK_URL }}`

The message:

Low stock: inventory item {{ event.payload.inventory_item_id }} has {{ event.payload.available }} left at location {{ event.payload.location_id }}

The rule sits on the trigger, not in a Condition step. Inventory changes all day; only the changes at or below your threshold start a run and count against your plan.

Make it yours

Select the trigger and change the filter's Value to your threshold.
Test as a preview. Set available in the Event (JSON). In a preview nothing is posted; the step shows the message it would have sent. Choose Run for real to see it arrive in Slack.
Save and Turn on.

Add the product name

Shopify's inventory event carries ids, not names. The template Low stock email with the product name shows the fix: look the item up first.

Press + above the Slack step and select Get Shopify data. Pick the query inventoryItem, or paste:

query ($id: ID!) {
  inventoryItem(id: $id) {
    sku
    variants(first: 1) { nodes { displayName product { title } } }
  }
}

Variables (JSON):

{ "id": "gid://shopify/InventoryItem/{{ event.payload.inventory_item_id }}" }

Run a Test, then pick the name for the message from the variable picker. With a step id of item it reads:

Low stock: {{ steps.item.output.inventoryItem.variants.nodes[0].displayName }} has {{ event.payload.available }} left

The query needs access to products as well.

One message, not ten

An item that goes from 5 to 4 to 3 posts three times. To be told once:

Use the change trigger Out of stock at location instead, which starts only at the moment an item reaches zero. See Change triggers with before and after values.
Or remember that you posted: a Key-value store step writes low:{{ event.payload.inventory_item_id }} with Forget after (seconds) set to a day, and a Condition before the message checks that the key is empty. See Key-value store and Storage.
Or send one summary a day with the template Daily low stock report by email.