Workflow Trigger ExtensionsWorkflow Trigger Extensions

Metafield triggers

Metafield triggers fire when a specific metafield definition changes, on any of 10 owner types. You choose which metafields to watch, one definition at a time, so a store with hundreds of metafields only ever fires for the ones a workflow cares about.

Supported owner types

Product, Product Variant, Collection, Customer, Order, Company, Company Location, Blog, Blog Post, and Page.

Setting one up

The example on this page watches a product metafield called Rating (custom.rating), the kind of value a reviews app writes.

1. Pick the metafield

  1. Open Metafield Triggers in the app navigation.
  2. Click Add Trigger.
  3. Choose the resource type the metafield belongs to, for example Product.
  4. Pick the metafield definition from the list - search by name if there are many - and click Add Trigger.

Only metafields with a definition are listed (Shopify admin, Settings, Custom data). The list is remembered for an hour, so a definition you created a moment ago may be missing: click Refresh Metafields next to Add Trigger and open the dialog again.

The Add Metafield Trigger dialog with resource type Product and the metafield Rating, custom.rating, selected
Choose the resource type, then the metafield definition. Search helps when there are many.

2. The metafield is now watched

The metafield appears in the list as Active. There is nothing else to switch on: adding it here is switching it on. Delete stops watching it.

The app first records the current value of that metafield on your existing records, so the very first edit already fires with the right old value.

The Metafield Triggers list with the product metafield Rating, custom.rating, shown as Active
The watched metafield, Active. Refresh Metafields reloads the list of definitions.

3. What an event carries

From then on, every edit to that metafield fires Metafield Update in Shopify Flow. The event carries the namespace and key, the record it belongs to, the new value, and previousValue - what the metafield said before. previousValue is empty when the metafield was just set for the first time.

In the example the rating went from 4.5 to 2.5. A workflow condition "value is less than 3 and previousValue is 3 or more" fires once, at the moment the rating drops below 3, instead of on every later edit. Step by step: Metafield triggers, step by step.

An event in Event History: Metafield Update for a product, value 2.5 and previousValue 4.5
One event, opened: the rating is now 2.5 and previousValue says it was 4.5.

The generic trigger and the typed ones

There are two ways to consume metafield changes:

Trigger Covers Delivers
Metafield Update All 10 owner types Namespace, key, owner id, old and new value
Order Metafield Update Orders only The same, plus the order as a native Flow reference
Product Metafield Update Products only The same, plus the product as a native reference
Customer Metafield Update Customers only The same, plus the customer as a native reference
Product Variant Metafield Update Product variants only The same, plus the parent product as a native reference

Use a typed trigger when your workflow needs to act on the resource itself, for example to tag the order or read its line items. The native reference means Flow can use its own Shopify actions on it directly, with no lookup step.

Use the generic trigger when you just need to know a value changed, or when you are watching an owner type that has no typed variant.

The typed triggers each have their own switch on the Triggers page (turning on a Flow workflow that uses one switches it on) and fire in addition to the generic trigger. They share one event, so enabling both does not double-count against your quota.

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