You can use delivery customizations to hide, reorder, and rename the delivery options that are available to buyers during checkout. In this tutorial, you'll use Shopify Functions to rename a delivery option offered to customers at checkout, based on the shipping destination.

## What you'll learn

In this tutorial, you’ll learn how to do the following tasks:

- Generate starter code for Shopify Functions.
- Use GraphQL to define the input of your function.
- Deploy functions to the Shopify platform.
- Review logs for your function.


![Screenshot that shows a renamed delivery option](/assets/apps/checkout/delivery-customization-rename-screenshot.png)

## Requirements



- You've created a [Partner account](https://www.shopify.com/partners).
- You've created a [development store](/docs/api/development-stores#create-a-development-store-to-test-your-app).
- You've [created an app that uses Shopify CLI 3.49.5 or higher](/docs/apps/build/scaffold-app). If you previously installed Shopify CLI, then make sure that you're using the [latest version](/docs/api/shopify-cli#upgrade).
  
    If you plan to create a UI for your extension, then start with the [Remix app template](/docs/api#app-templates).
  
  
- You've installed [Node.js](https://nodejs.org/en/download) 16 or higher.
- You've [installed your app](/docs/apps/build/scaffold-app#step-3-install-your-app-on-your-development-store) on the development store.




### Rust-specific requirements

The following requirements are specific to Rust-based development with Shopify Functions.

- You've installed [Rust](https://www.rust-lang.org/tools/install).

    On Windows, Rust requires the [Microsoft C++ Build Tools](https://docs.microsoft.com/en-us/windows/dev-environment/rust/setup). Make sure to select the **Desktop development with C++** workload when installing the tools.

- You've installed the [`wasm32-wasip1` target](https://doc.rust-lang.org/rustc/platform-support/wasm32-wasip1.html):

    <p>
    <div class="react-code-block" data-preset="terminal">
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    <div class="react-code-block-preload-bar "></div>
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    <div class="react-code-block-preload-codeline-number"></div>
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    </div>

    </div>
    </div>


    <script type="text/plain" data-language="bash">
    RAW_MD_CONTENTrustup target add wasm32-wasip1
    END_RAW_MD_CONTENT</script>

    </div>
    </p>




## Limitations

- In the Delivery Customization API, the carrier name is automatically prepended to the shipping method title at checkout when using the [RenameOperation](/docs/api/functions/reference/delivery-customization/graphql/common-objects/renameoperation), and cannot be altered or omitted through the API. For example, if the carrier name is `UPS` and the method is `Standard`, you could change `UPS Standard` to `UPS Standard Shipping`, but you couldn't change `UPS Standard` to `Standard Shipping`.


## Sample code

If you want to quickly get started, then you can get the sample code by completing the following steps. This tutorial describes the sample code step by step.

1. Clone the delivery customizations sample app:

    <p>
    <div class="react-code-block" data-preset="terminal">
    <div class="react-code-block-preload ThemeMode-dim">
    <div class="react-code-block-preload-bar "></div>
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    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>

    </div>
    </div>


    <script type="text/plain" data-language="bash">
    RAW_MD_CONTENTshopify app init --template https://github.com/Shopify/function-examples/sample-apps/delivery-customizations
    END_RAW_MD_CONTENT</script>

    </div>
    </p>


    > Note:
    > You can [view the source code for the delivery customizations sample app](https://github.com/Shopify/function-examples/tree/main/sample-apps/delivery-customizations) in GitHub.

1. Enter a name for your app project.

1. Navigate to your app directory:

    <p>
    <div class="react-code-block" data-preset="terminal">
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    <div class="react-code-block-preload-bar "></div>
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    </div>

    </div>
    </div>


    <script type="text/plain" data-language="bash">
    RAW_MD_CONTENTcd <directory>
    END_RAW_MD_CONTENT</script>

    </div>
    </p>


1. Link your app configuration:

    <p>
        <div class="react-code-block" data-preset="terminal">
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        <div class="react-code-block-preload-bar "></div>
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        <div class="react-code-block-preload-codeline"></div>
        </div>

        </div>
        </div>


        <script type="text/plain" data-language="bash">
        RAW_MD_CONTENTshopify app config link
        END_RAW_MD_CONTENT</script>

        </div>
        </p>


1. Start a local server for your app:

    <p>
        <div class="react-code-block" data-preset="terminal">
        <div class="react-code-block-preload ThemeMode-dim">
        <div class="react-code-block-preload-bar "></div>
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        </div>

        </div>
        </div>


        <script type="text/plain" data-language="bash">
        RAW_MD_CONTENTshopify app dev 
        END_RAW_MD_CONTENT</script>

        </div>
        </p>


1. With the server running, open the **Preview URL** in the terminal output.

    When you open the URL, you're prompted to install the app on your development store.

1. Click **Install app** to install the app on the store.




1. [Create and test your delivery customization](/docs/apps/build/checkout/delivery-shipping/delivery-options/build-ui#step-5-create-and-test-your-delivery-customization).

## Step 1: Create the delivery customization function

To create your delivery customization function, you can use Shopify CLI to [generate](/docs/api/shopify-cli/app/app-generate-extension) a starter function, specify the inputs for your function using an [input query](/docs/apps/build/functions/input-output/metafields-for-input-queries), and implement your function logic using JavaScript or Rust.

1. Navigate to your app directory:

    <p>
    <div class="react-code-block" data-preset="terminal">
    <div class="react-code-block-preload ThemeMode-dim">
    <div class="react-code-block-preload-bar "></div>
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    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>

    </div>
    </div>


    <script type="text/plain" data-language="bash">
    RAW_MD_CONTENTcd <directory>
    END_RAW_MD_CONTENT</script>

    </div>
    </p>


1. Run the following command to create a new delivery customization extension:

    <p>
        <div class="react-code-block" data-preset="terminal">
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        <div class="react-code-block-preload-bar "></div>
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        </div>

        </div>
        </div>


        <script type="text/plain" data-language="bash">
        RAW_MD_CONTENTshopify app generate extension --template delivery_customization --name delivery-customization
        END_RAW_MD_CONTENT</script>

        </div>
        </p>


1.  Choose the language that you want to use. For this tutorial, you should select either **Rust** or **JavaScript**.

    Shopify defaults to Rust as the most performant and recommended language choice to stay within the platform limits. For more information, refer to [language considerations](/docs/apps/build/functions/programming-languages).


    <p>
    <div class="react-code-block" data-preset="terminal">
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    </div>

    </div>
    </div>


    <script type="text/plain" data-language="bash">
    RAW_MD_CONTENT?  What would you like to work in?
    > (1) Rust
      (2) JavaScript
      (3) TypeScript
      (4) Wasm
    END_RAW_MD_CONTENT</script>

    </div>
    </p>



1. Navigate to `extensions/delivery-customization`:

    <p>
    <div class="react-code-block" data-preset="terminal">
    <div class="react-code-block-preload ThemeMode-dim">
    <div class="react-code-block-preload-bar "></div>
    <div class="react-code-block-preload-placeholder-container">
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>

    </div>
    </div>


    <script type="text/plain" data-language="bash">
    RAW_MD_CONTENTcd extensions/delivery-customization
    END_RAW_MD_CONTENT</script>

    </div>
    </p>


1. Replace the contents of `src/run.graphql` file with the following code.

    `run.graphql` defines the input for the function. You need the cart delivery groups, with the delivery state/province code and available delivery options.

    The query differs slightly in Rust and JavaScript due to code generation requirements.

    <p>
    <div class="react-code-block" data-preset="file">
    <div class="react-code-block-preload ThemeMode-dim">
    <div class="react-code-block-preload-bar "></div>
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    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
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    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>

    </div>
    </div>

    <script data-option="filename" data-value="run.graphql"></script>

    <script type="text/plain" data-language="graphql" data-title="Rust input query" data-filename="src/run.graphql">
    RAW_MD_CONTENTquery Input {
      cart {
        deliveryGroups {
          deliveryAddress {
            provinceCode
          }
          deliveryOptions {
            handle
            title
          }
        }
      }
    }
    END_RAW_MD_CONTENT</script>
<script type="text/plain" data-language="graphql" data-title="JavaScript input query" data-filename="src/run.graphql">
    RAW_MD_CONTENTquery RunInput {
      cart {
        deliveryGroups {
          deliveryAddress {
            provinceCode
          }
          deliveryOptions {
            handle
            title
          }
        }
      }
    }
    END_RAW_MD_CONTENT</script>

    </div>
    </p>


1. If you're using JavaScript, then run the following command to regenerate types based on your input query:

    <p>
    <div class="react-code-block" data-preset="terminal">
    <div class="react-code-block-preload ThemeMode-dim">
    <div class="react-code-block-preload-bar "></div>
    <div class="react-code-block-preload-placeholder-container">
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>

    </div>
    </div>


    <script type="text/plain" data-language="bash">
    RAW_MD_CONTENTshopify app function typegen
    END_RAW_MD_CONTENT</script>

    </div>
    </p>



1. Replace the `src/run.rs` or `src/run.js` file with the following code.

    This function logic appends a message to all delivery options if the shipping address state or province code is `NC`. You can adjust this to the state or province of your choice.

    <p>
    <div class="react-code-block" data-preset="file">
    <div class="react-code-block-preload ThemeMode-dim">
    <div class="react-code-block-preload-bar "></div>
    <div class="react-code-block-preload-placeholder-container">
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>
    <div class="react-code-block-preload-code-container">
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    <div class="react-code-block-preload-codeline"></div>
    </div>
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
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    </div>
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    <script type="text/plain" data-language="rust" data-title="Rust" data-filename="src/run.rs">
    RAW_MD_CONTENTuse shopify_function::prelude::*;
    use shopify_function::Result;
    
    // The configured entrypoint for the 'purchase.delivery-customization.run' extension target
    #[shopify_function_target(query_path = "src/run.graphql", schema_path = "schema.graphql")]
    fn run(input: input::ResponseData) -> Result<output::FunctionRunResult> {
        // The message we wish to add to the delivery option
        let message = "May be delayed due to weather conditions";
    
        let to_rename = input
            .cart
            .delivery_groups
            .iter()
            // Filter for delivery groups with a shipping address containing the affected state or province
            .filter(|group| {
                let state_province = group
                    .delivery_address
                    .as_ref()
                    .and_then(|address| address.province_code.as_ref());
                match state_province {
                    Some(code) => code == "NC",
                    None => false,
                }
            })
            // Collect the delivery options from these groups
            .flat_map(|group| &group.delivery_options)
            // Construct a rename operation for each, adding the message to the option title
            .map(|option| output::RenameOperation {
                delivery_option_handle: option.handle.to_string(),
                title: match &option.title {
                    Some(title) => format!("{} - {}", title, message),
                    None => message.to_string(),
                },
            })
            // Wrap with an Operation
            .map(output::Operation::Rename)
            .collect();
    
        // The shopify_function crate serializes your function result and writes it to STDOUT
        Ok(output::FunctionRunResult {
            operations: to_rename,
        })
    }
    END_RAW_MD_CONTENT</script>
<script type="text/plain" data-language="javascript" data-title="JavaScript" data-filename="src/run.js">
    RAW_MD_CONTENT// @ts-check
    
    // Use JSDoc annotations for type safety
    /**
    * @typedef {import("../generated/api").RunInput} RunInput
    * @typedef {import("../generated/api").FunctionRunResult} FunctionRunResult
    * @typedef {import("../generated/api").Operation} Operation
    */
    
    // The configured entrypoint for the 'purchase.delivery-customization.run' extension target
    /**
    * @param {RunInput} input
    * @returns {FunctionRunResult}
    */
    export function run(input) {
      // The message to be added to the delivery option
      const message = "May be delayed due to weather conditions";
    
      let toRename = input.cart.deliveryGroups
        // Filter for delivery groups with a shipping address containing the affected state or province
        .filter(group => group.deliveryAddress?.provinceCode &&
          group.deliveryAddress.provinceCode == "NC")
        // Collect the delivery options from these groups
        .flatMap(group => group.deliveryOptions)
        // Construct a rename operation for each, adding the message to the option title
        .map(option => /** @type {Operation} */({
          rename: {
            deliveryOptionHandle: option.handle,
            title: option.title ? `${option.title} - ${message}` : message
          }
        }));
    
      // The @shopify/shopify_function package applies JSON.stringify() to your function result
      // and writes it to STDOUT
      return {
        operations: toRename
      };
    };
    END_RAW_MD_CONTENT</script>

    </div>
    </p>


## Step 2: Preview the function on a development store

To test your function, you need to make it available to your development store.

1. If you're developing a function in a language other than JavaScript or TypeScript, ensure you have configured `build.watch` in your [function extension configuration](/docs/api/functions/configuration#properties).




1. Navigate back to your app root:

    <p>
    <div class="react-code-block" data-preset="terminal">
    <div class="react-code-block-preload ThemeMode-dim">
    <div class="react-code-block-preload-bar "></div>
    <div class="react-code-block-preload-placeholder-container">
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    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>

    </div>
    </div>


    <script type="text/plain" data-language="bash">
    RAW_MD_CONTENTcd ../..
    END_RAW_MD_CONTENT</script>

    </div>
    </p>



1. Use the Shopify CLI [`dev` command](/docs/api/shopify-cli/app/app-dev) to start app preview:

    <p>
    <div class="react-code-block" data-preset="terminal">
    <div class="react-code-block-preload ThemeMode-dim">
    <div class="react-code-block-preload-bar "></div>
    <div class="react-code-block-preload-placeholder-container">
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    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>

    </div>
    </div>


    <script type="text/plain" data-language="bash">
    RAW_MD_CONTENTshopify app dev 
    END_RAW_MD_CONTENT</script>

    </div>
    </p>


    You can keep the preview running as you work on your function. When you make changes to a watched file, Shopify CLI rebuilds your function and updates the function extension's drafts, so you can immediately test your changes.

1. Follow the CLI prompts to preview your app, and install it on your development store.


## Step 3: Create the delivery customization with GraphiQL

To activate your function, you must create a delivery customization on the store where you installed your app. You can do this using the [`deliveryCustomizationCreate`](/docs/api/admin-graphql/current/mutations/deliveryCustomizationCreate) GraphQL mutation.

In subsequent tutorials, you'll use metafields on this delivery customization to configure your function, and create a user interface so merchants can configure the function themselves.

1. Install the [Shopify GraphiQL app](https://shopify-graphiql-app.shopifycloud.com/) on your store. If you've already installed GraphiQL, then you should do so again to select the necessary access scopes for delivery customizations.

    > Note:
    > Make sure to select the `read_delivery_customizations` and `write_delivery_customizations` access scopes for the Admin API.
1. In the GraphiQL app, in the **API Version** field, select the **2023-07** version.



1. Find the ID of your function by executing the following query:

    <p>
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    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
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    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
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    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>

    </div>
    </div>

    <script data-option="filename" data-value="find-function-query.graphql"></script>

    <script type="text/plain" data-language="graphql">
    RAW_MD_CONTENTquery {
      shopifyFunctions(first: 25) {
        nodes {
          app {
            title
          }
          apiType
          title
          id
        }
      }
    }
    END_RAW_MD_CONTENT</script>

    </div>
    </p>


    The result contains a node with your function's ID:

    <p>
    <div class="react-code-block" data-preset="file">
    <div class="react-code-block-preload ThemeMode-dim">
    <div class="react-code-block-preload-bar "></div>
    <div class="react-code-block-preload-placeholder-container">
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>

    </div>
    </div>

    <script data-option="filename" data-value="find-function-result.json"></script>

    <script type="text/plain" data-language="json">
    RAW_MD_CONTENT{
      "app": {
        "title": "your-app-name-here"
      },
      "apiType": "delivery_customization",
      "title": "delivery-customization",
      "id": "YOUR_FUNCTION_ID_HERE"
    }
    END_RAW_MD_CONTENT</script>

    </div>
    </p>



1. Execute the following mutation and replace `YOUR_FUNCTION_ID_HERE` with the ID of your function:

    <p>
    <div class="react-code-block" data-preset="file">
    <div class="react-code-block-preload ThemeMode-dim">
    <div class="react-code-block-preload-bar "></div>
    <div class="react-code-block-preload-placeholder-container">
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>
    <div class="react-code-block-preload-code-container">
    <div class="react-code-block-preload-codeline-number"></div>
    <div class="react-code-block-preload-codeline"></div>
    </div>
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    <script data-option="filename" data-value="mutation.graphql"></script>

    <script type="text/plain" data-language="graphql">
    RAW_MD_CONTENTmutation {
      deliveryCustomizationCreate(deliveryCustomization: {
        functionId: "YOUR_FUNCTION_ID_HERE"
        title: "Add message to delivery options for state/province"
        enabled: true
      }) {
        deliveryCustomization {
          id
        }
        userErrors {
          message
        }
      }
    }
    END_RAW_MD_CONTENT</script>

    </div>
    </p>


    You should receive a GraphQL response that includes the ID of the created delivery customization. If the response includes any messages under `userErrors`, then review the errors, check that your mutation and `functionId` are correct, and try the request again.

    > Tip:
    > If you receive a `Could not find Function` error, then confirm the following:
    >
    > - The function ID is correct.
    > - You've installed the app on your development store.
    > - [Development store preview](#step-2-preview-the-function-on-a-development-store) is enabled.

## Step 4: Test the delivery customization

1. From the Shopify admin, go to **Settings** > **Shipping and delivery**.
1. Check the **Delivery customizations** section. You should find the **Add message to delivery options for state/province** delivery customization that you created with GraphiQL.

1. Open your development store, build a cart, and proceed to checkout.
1. Enter a delivery address that doesn't use the specified state/province code. You shouldn't see any additional messaging on the delivery options.
1. Change your shipping address to use your chosen state/province code. Your delivery options should now have the additional messaging.
1. Open your terminal where `shopify app dev` is running, and review your function executions.

    When [testing functions on development stores](/docs/apps/build/functions/test-debug-functions#test-your-function-on-a-development-store), the output of `dev` includes executions of your functions, any debug logging you have added to them, and a link to a local file with the full function execution details.
1. In a new terminal window, use the Shopify CLI [`app function replay`](/docs/api/shopify-cli/app/app-function-replay) command to [replay a function execution locally](/docs/apps/build/functions/test-debug-functions#execute-the-function-locally-using-shopify-cli), and debug your function without the need to re-trigger the function execution on Shopify.

    <p>
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    </div>

    </div>
    </div>


    <script type="text/plain" data-language="bash">
    RAW_MD_CONTENTshopify app function replay
    END_RAW_MD_CONTENT</script>

    </div>
    </p>


1. Select the function execution from the top of the list. Press `q` to quit when you are finished debugging.



## Next steps

- [Add configuration](/docs/apps/build/checkout/delivery-shipping/delivery-options/add-configuration) to your delivery customization using metafields.