createdAt is now available on the Customer object in Shopify Functions

Shopify Functions API version 2026-10 adds a createdAt field to the Customer object. You can now use the date and time a customer account was created in Function logic. This is an additive change; no action is required for existing Functions.

What changed

The Customer object now exposes createdAt, which returns the date and time when the customer account was created. This lets you build customizations based on when a customer joined.

To use createdAt, request it from the customer on Cart.buyerIdentity in the Function input query:

query Input {
  cart {
    buyerIdentity {
      customer {
        createdAt
      }
    }
  }
}

The customer is available only when the buyer is signed in. Functions should continue to handle guest buyers, where buyerIdentity or customer might be null or omitted.

Earlier Shopify Functions API versions are unchanged. To use the new field:

• Update the Function to API version 2026-10.
• Add createdAt to the Function’s input query.
• Test with both signed-in and guest buyers.

Related docs

• Shopify Functions API reference
• Shopify Functions input queries