About Shopify Function APIs

• All plans: Except as noted below, stores on any plan can use public apps that are distributed through the Shopify App Store and contain functions.

• Shopify Plus: Only stores on a Shopify Plus plan can use custom apps that contain Shopify Function APIs.

The following Function APIs are available:

Learn how to use Shopify Functions by following one of our use case tutorials:

Build a discount function

Use Shopify Functions to create a new discount type for users.

Create a payments function

Use Shopify Functions to hide a payment option offered to customers at checkout.

Build a delivery options function

Use Shopify Functions to rename a delivery option offered to customers at checkout.

Create server-side validation

Use Shopify Functions to block progress on a checkout when the cart line quantities exceed a limit.

Build a location rule function

Use Shopify Functions to choose a different order location during checkout.

Add a customized bundle

Use Shopify Functions to group products together and sell them as a single unit.

Build fulfillment constraints

Use Shopify Functions to customize fulfillment and delivery strategies.

Build local pickup options

Use Shopify Functions to generate local pickup delivery options at checkout.

Generate pickup points

Use Shopify Functions to generate pickup point delivery options at checkout.

Explore the developer tools and resources available for Shopify Functions.

Shopify Function APIs reference

Learn about the available APIs for Shopify Functions.

Language support

Learn about the language support and tooling that are available in Shopify Functions.

Function APIs are versioned. Updates are released quarterly and supported API versions are listed in the release notes.

Learn how to update to a new version of a Function API.

The following limitations and considerations apply to all functions:

• Apps can reference only their own functions in GraphQL Admin API mutations, such as discountAutomaticAppCreate and cartTransformCreate. Referencing a function from another app results in a Function not found error.
• Shopify doesn't allow nondeterminism in functions, which means that you can't use any randomizing or clock functionality in your functions.
• You can't debug your function by printing out STDOUT, which is reserved for function output. Use STDERR instead.
• Apps that provide dynamic editing and execution of function code aren't permitted on the Shopify App Store.
• Network access is supported for some functions, refer to network access for more information. You can also pre-populate data by using metafields on products and customers, or passing data using cart attributes.

The following resource limits apply to all functions:

Certain limits are dynamic and scale based on the number of line items in a cart. The following resource limits apply to all functions for carts with up to 200 line items:

For carts with more than 200 line items, these values will scale proportionally as the number of cart lines increases. Calculated limits for a function execution are available in your Partner Dashboard and can be tested with Shopify CLI.

• Learn about how Shopify Functions work and the benefits of using Shopify Functions.
• Learn about how data is input to and output from Shopify Functions.