Configuring app extensions

When you generate an app extension, a TOML configuration file named shopify.extension.toml is automatically generated in your app's extension directory.

How it works

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Shopify CLI builds and serves app extensions using information defined in a TOML file named shopify.extension.toml. The TOML file is located in a directory within the extensions/ directory of your app project.

The following example shows a shopify.extension.toml file that contains configuration settings for a checkout UI extension.

Extension types

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Some extensions require specific configurations. To accommodate this, Shopify CLI groups extensions into different types in the TOML file:

Extension	`type` value in the TOML file	`--template` flag value in the generate command
Checkout UI Developer preview	`ui_extension`	`checkout_ui`
Customer account UI Developer preview	`ui_extension`	`customer_account_ui`
Admin action	`ui_extension`	`admin_action`
Admin block	`ui_extension`	`admin_block`
Product configuration	`ui_extension`	`product_configuration`
Shopify Flow trigger	`flow_trigger`	`flow_trigger`
Shopify Flow action	`flow_action`	`flow_action`
Order discount	`function`	`order_discounts`
Product discount	`function`	`product_discounts`
Shipping discount Developer preview	`function`	`shipping_discounts`
Discounts allocator Developer preview	`function`	`discounts_allocator`
Delivery customization	`function`	`delivery_customization`
Payment customization	`function`	`payment_customization`
Order routing location rule Beta	`function`	`order_routing_location_rule`
Cart and checkout validation	`function`	`cart_checkout_validation`
Cart transform	`function`	`cart_transform`
Fulfillment constraints	`function`	`fulfillment_constraints`

Targets

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A target is an identifier in shopify.extension.toml that specifies where you're injecting code into Shopify APIs, or other parts of the Shopify platform.

Each target is composed of three to four namespaces. The name begins with a broad Shopify context and ends with the behavior of the extensible element. For example, a checkout UI extension that renders a shipping address form has a target named purchase.checkout.delivery-address.render-before:

purchase: The broad Shopify context.
checkout: The targeted page.
delivery-address: The element that the extension will be positioned near.
render-before: An action verb that describes the behavior of the extensible element.

Supported targets

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The following table provides links to documentation on the supported targets associated with each app extension type.

Extension type	Documentation on supported targets
Checkout UI	Checkout UI targets
Customer account UI	Customer Account UI targets
Admin UI	Admin UI targets
Product configuration	Product configuration app extensions use the admin.product-details.configuration.render or admin.product-variant-details.configuration.render target.
Shopify Functions	Shopify function APIs and targets The available targets depend on the Function APIs that you're using.

Common properties

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This section describes the configuration settings in shopify.extension.toml that are common to checkout UI extensions, admin UI, product configuration, Shopify Flow triggers, Shopify Flow actions, and Shopify Functions extensions.

Property	Description
`api_version` Required	The version of the API that's being used for the extension. If provided in the `[[extensions]]` array, then the specified API version is used instead of the root level `api_version`.
`[[extensions]]` Required	The name of the array that contains all extensions listed in the TOML file. Contains the following properties: `name`:Required The merchant-facing name of the extension. After you generate an extension, you're prompted to provide a name for your extension. The `name` property is translatable if it starts with a `t:` and uses a key defined in your translation data. For example, you might have a `t:name` key that matches a translation key called `name`. Learn more about localization. Limitations: Supports any characters. Shopify Flow actions and Shopify Flow triggers extensions can only include alphanumeric characters and spaces. 5 characters minimum 30 characters maximum `description`:Required The merchant-facing description of the extension. The `description` property is translatable if it starts with a `t:` and uses a key defined in your translation data. For example, `t:description` and you have a matching translation key called `description`. Learn more about localization. `handle`:Required The unique internal identifier for the extension. After you create a draft version of the extension, or deploy an extension, you can't change the `handle` value. If not specified, the `handle` value is automatically populated using a transformed `name` value that removes any unsupported characters. For example, if you enter `google maps` as the extension name, then Shopify populates the `handle` value as `google-maps`. Limitations: Allowed characters: `a-z`, `A-Z`, `0-9`, `-` 100 characters maximum Must be unique within the app `type`:Required The extension type. For more information, refer to Extension types.
`[settings]` Optional	The name of the array that defines settings that a merchant can set values for. If provided in the `[[extensions]]` array, then the specified settings are used instead of the root level `settings`.
`[[settings.fields]]` Optional	The name of the array that contains the settings fields.
`[[extensions.targeting]]` Required	The name of the array that contains a target and path to the related extension code. Contains the following required properties: `target`:Required An identifier that specifies where you're injecting code into Shopify APIs, or other parts of the Shopify platform. For more information, refer to Targets. `module`:Required The file that contains the extension code.

Extension-specific properties

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This section describes the configuration settings in shopify.extension.toml that are specific to the following extensions:

Checkout UI extensions
Customer account UI extensions
Admin UI extensions
Product configuration extensions
Shopify Flow actions
Shopify Flow triggers
Shopify Functions extensions

Checkout UI extensions

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The following example TOML file contains configuration settings for a checkout UI extension:

The following table describes the properties in the TOML file that are specific to checkout UI extensions:

Property	Description
`[extensions.capabilities]` Optional	The name of the array that contains the checkout UI extension's capabilities: `api_access`:Optional Whether your app extension can query the Storefront API. `block_progress`:Optional Whether your app extension can block the customer's progress. `network_access`:Optional Whether your app extension can make external network calls.
`[extensions.metafields]` Optional	An array that sets the default for each `[[extensions.targeting.metafields]]`, if `[[extensions.targeting.metafields]]` isn't specified.
`[[extensions.targeting.metafields]]` Optional	The metafields that your extension target needs to read: `key`:Optional The name for the metafield. `namespace`:Optional A container for a group of metafields. Grouping metafields within a namespace prevents your metafields from conflicting with other metafields with the same key name. You can specify up to five `key` and `namespace` pairs in the configuration file. When the extension is executed, Shopify looks for the metafields in each resource and returns their contents.

Customer account UI extensions

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The following example TOML files contain configuration settings for a static and a full page extension. The properties in the TOML files are similar to checkout UI extensions:

The following table describes the properties in the TOML file that are specific to customer account UI extensions:

Property	Required?	Description
`[extensions.capabilities]`	No	The name of the array that contains the checkout UI extension's capabilities: `api_access`: Whether your app extension can query the Storefront API. `network_access`: Whether your app extension can make external network calls.
`[extensions.metafields]`	No	An array that sets the default for each `[[extensions.targeting.metafields]]`, if `[[extensions.targeting.metafields]]` isn't specified.
`[[extensions.targeting.metafields]]`	No	The metafields that your extension target needs to read: `key`: The name for the metafield. `namespace`: A container for a group of metafields. Grouping metafields within a namespace prevents your metafields from conflicting with other metafields with the same key name. You can specify up to five `key` and `namespace` pairs in the configuration file. When the extension is executed, Shopify looks for the metafields in each resource and returns their contents.

Admin UI extensions

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The following example TOML files contain configuration settings for an action and a block extension. The properties in the TOML files are similar to checkout UI extensions:

Product configuration extensions

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The following example TOML file contains configuration settings for a product configuration extension. The properties in the TOML file are similar to a checkout UI extension:

Shopify Flow actions

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The following example TOML file contains configuration settings for a Shopify Flow action:

The following table describes the properties in the TOML file that are specific to a Shopify Flow action:

Property Description

Property	Description
`[[extensions]]` Required	The name of the array that contains all extensions listed in the TOML file. Contains the following properties: `runtime_url`:Required The endpoint where Flow sends your action's payload when your step is being executed at runtime. The payload contains data that you can use to execute the action in your app. `validation_url`:Optional An endpoint that validates the contents of custom properties in an action payload when an action is saved. This endpoint is only required if you want to use a custom configuration page. `schema`:Optional A relative path to a GraphQL schema definition file that contains custom types that you can use as part of your action. Only required if `return_type_ref` is also present. `return_type_ref`:Optional The name of the type to be returned by the action. This type must be present in the referenced schema file. Only required if `schema` is also present. `config_page_url`:Optional A route that renders your custom configuration page. `config_page_preview_url`:Optional An endpoint that provides data about your custom configuration page to display in the automation tool. This endpoint is only required if you want to use a custom configuration page.
`[[settings.fields]]` Required	The name of the array that contains the settings fields. Contains the following property: `required`:Required Specifies whether a field is required (`true`) or optional (`false`).

[[extensions]]
Required

The name of the array that contains all extensions listed in the TOML file. Contains the following properties:

runtime_url:Required The endpoint where Flow sends your action's payload when your step is being executed at runtime. The payload contains data that you can use to execute the action in your app.
validation_url:Optional An endpoint that validates the contents of custom properties in an action payload when an action is saved. This endpoint is only required if you want to use a custom configuration page.
schema:Optional A relative path to a GraphQL schema definition file that contains custom types that you can use as part of your action. Only required if return_type_ref is also present.
return_type_ref:Optional The name of the type to be returned by the action. This type must be present in the referenced schema file. Only required if schema is also present.
config_page_url:Optional A route that renders your custom configuration page.
config_page_preview_url:Optional An endpoint that provides data about your custom configuration page to display in the automation tool. This endpoint is only required if you want to use a custom configuration page.

[[settings.fields]]
Required

The name of the array that contains the settings fields. Contains the following property:

required:Required Specifies whether a field is required (true) or optional (false).

Shopify Flow triggers

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The following example TOML file contains configuration settings for a Shopify Flow trigger. The properties in the TOML file are similar to a Shopify Flow action:

Shopify Functions extensions

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The following example TOML file contains configuration settings for a Shopify Function extension:

The following table describes the properties in the TOML file that are specific to a Shopify Function extension:

Property	Description
`[[extensions.targeting]]` Required	The name of the array that contains a target and its associated WebAssembly module export. Contains the following properties: `target`:Required An identifier that specifies where you're injecting code into the Shopify backend. Refer to the Function API references for available function targets. `input_query`:Optional The path to the input query file for the target. If omitted, then the function receives no input. `export`:Optional The name of the WebAssembly export in your module that executes for the target. Functions don't use the `extensions.targeting.module` setting. Use `export` instead. Defaults to `_start`.
`[extensions.build]` Optional	The settings related to the build and deployment of the function extension's WebAssembly module. Contains the following properties: `command`:Optional The command to build the function, which is invoked by the Shopify CLI `build` command. `path`:Optional The relative path to the function's WebAssembly module. For example, `build/my-module.wasm`. Defaults to `dist/index.wasm`. `watch`:Optional The relative paths that Shopify CLI should watch when the `dev` command is invoked. Changes to matched files trigger a build of the function and update it in your application drafts. This setting accepts a single file path or glob pattern, or an array of file paths and glob patterns. For JavaScript and TypeScript functions, this setting defaults to `['src/*/.js', 'src/*/.ts']`. Input queries are automatically included in watch paths and don't need to be configured in `build.watch`.
`[extensions.ui]` Optional	The settings related to the merchant interface for your function. Contains the following properties: `handle`: Optional Learn how to create your function merchant interface. `enable_create`:Optional Learn how to configure creation workflows for function owners.
`[extensions.ui.paths]` Optional	The settings related to the App Bridge paths of the merchant interface for your function. Contains the following properties: `create`:Optional Refer to create your function merchant interface. `details`:Optional Refer to create your function merchant interface.
`[extensions.input.variables]` Optional	The variables to use in your input query. Contains the following properties: `key`: The name for the metafield. `namespace`: A container for a group of metafields. Grouping metafields within a namespace prevents your metafields from conflicting with other metafields with the same key name.

Differences in TOML file names

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TOML file names can differ, depending on when you generated an extension:

If you generated an extension before July 26, 2023, then your TOML file maps to one of the following names:
- Checkout UI: shopify.ui.extension.toml
- Bundles UI extension: shopify.ui.extension.toml (maps to a product configuration extension)
- Post-purchase UI: shopify.ui.extension.toml
- Product subscription: shopify.ui.extension.toml
- Web pixel: shopify.ui.extension.toml
- Shopify POS UI: shopify.ui.extension.toml
- Shopify Functions: shopify.function.extension.toml
- Theme app extensions: shopify.theme.extension.toml
If you generated an extension after July 26, 2023, then the TOML file is named shopify.extension.toml.