Build a discounts UI with Remix
To build a UI that merchants can use to configure a Discount Function, you can use Admin UI Extensions to display a form on the discount details page, or you can add a page to a Remix app. This tutorial describes how to add a page to a Remix app, which will render the Discount Function editing UI at a path of your own specification.
Anchor to What you'll learnWhat you'll learn
In this tutorial, you'll learn how to do the following tasks:
-
Scaffold a Remix app with the Shopify CLI
Build your app using the provided template with all necessary components.
-
Review frontend UI components
Explore the app structure, including routes, forms, and Polaris components that create the merchant interface for discount configuration.
-
Set up a discount Function
Configure the discount function to handle product, order, and shipping discounts using metafields and GraphQL operations.
-
Deploy the app to Shopify
Push your app to Shopify and install it in your development store.
-
Configure a test discount
Using your app's interface, create an automatic discount with specific percentages for products, orders, and shipping.
-
Verify the discount functionality
Test the discount in your development store's cart and checkout flow, confirming all discount types apply correctly.

Requirements
Project
Anchor to Scaffold the Remix appScaffold the Remix app
To scaffold a complete Remix app, run this command to set up your development environment with a fully functional Remix app.
Terminal
This command sets up your development environment with a fully functional Remix app. The next steps walk you through the key components.
Anchor to Understand the discount configuration UIUnderstand the discount configuration UI
The app structure includes these key directories.
- 📁
components/
Reusable UI components - 📁
graphql/
GraphQL queries and mutations for functions, collections, and discounts - 📁
hooks/
Custom React hooks, includinguseDiscountForm
for discount management - 📁
routes/
Remix routes handling app navigation, authentication, and discount management - 📁
types/
TypeScript definitions including form types, admin types, and generated types - 📁
utils/
Utility functions including navigation helpers
The app integrates @shopify/polaris components to match the Shopify admin interface.
Anchor to Review routes, UI components, and discount configurationReview routes, UI components, and discount configuration
The route files manage discount creation and editing.
Anchor to Ensure the correct access scopes are setEnsure the correct access scopes are set
Review the shopify.app.toml
file to ensure the correct access scopes are set. Your app needs write_discounts
and read_products
scopes.
Anchor to Explore the create discount routeExplore the create discount route
Review the discount creation logic in the create route file.
The action
function processes form submissions through the discountCodeAppCreate
mutation.
Anchor to Examine the edit discount routeExamine the edit discount route
To understand discount editing, review the edit route file.
Anchor to Review the ,[object Object], componentReview the DiscountForm
component
DiscountForm
componentThe DiscountForm component is responsible for rendering the form that allows merchants to configure the discount:
This form includes fields required by the discount creation mutation:
title
method
code
combinesWith
discountClasses
usageLimit
appliesOncePerCustomer
startsAt
endsAt
metafield
Anchor to Understand the ,[object Object], configurationUnderstand the discountClasses
configuration
discountClasses
configurationThe form includes a section for selecting discount classes. This section allows merchants to apply discounts to PRODUCT
, ORDER
, and SHIPPING
classes.
Anchor to Review the discount percentage configurationReview the discount percentage configuration
Examine how merchants set discount percentages.
This section of the form allows merchants to set the discount percentage for each class, using a number input.
Anchor to Explore the ,[object Object], componentExplore the CollectionPicker
component
CollectionPicker
componentReview how collection selection works.
This section uses the AppBridge ResourcePicker
component to allow merchants to select collections, to make sure that discounts are applied to the expected products.
The discount configuration uses metafields for storage. Learn more about using metafields with input queries.
Anchor to Review server-side discount managementReview server-side discount management
To learn how the Remix app handles server-side operations, examine the files in the app/models directory. These files query and mutate resources using Shopify's GraphQL Admin API.
Anchor to Explore functions server fileExplore functions server file
This file queries the Functions associated with your app. We use this query to populate the functionId
field used in the discountAutomaticAppCreate
and discountCodeAppCreate
mutations.
Anchor to Review collections server fileReview collections server file
This file handles collection data stored in discount metafields. We use this query to populate the list of collections displayed in the section where merchants can select collections to target with the discount. When editing a discount, we use this query to populate the list of collections displayed below the resource picker.
Anchor to Examine discounts server fileExamine discounts server file
This file manages discount creation, updates, and retrieval. We use this file to create, read, and update discounts.
Anchor to Review GraphQL operationsReview Graph QL operations
In this step, you'll examine the app's GraphQL queries and mutations. These operations communicate with the Shopify Admin GraphQL API to create, read, and update discounts, retrieve collections, and retrieve functions.
Anchor to Review discount graphql fileReview discount graphql file
These queries and mutations handle, retrieving discounts, creating code and automatic discounts, and updating code and automatic discounts.
Anchor to Examine collections graphql fileExamine collections graphql file
This file contains queries for collection data which is used to populate the list of collections displayed in the section where merchants can select collections. When editing a discount, we use this query to populate the list of collections displayed below the resource picker.
Anchor to Review functions graphql fileReview functions graphql file
This query returns functions for your app when the app is installed on a merchant's store. This example uses this query to populate the app's home page, which allows you to navigate to the create discount page and it also populates the functionId
field used in the discountAutomaticAppCreate
and discountCodeAppCreate
mutations.
Anchor to Set up the Discount FunctionSet up the Discount Function
Now, create a Discount Function. This function will be used to apply discounts to products, orders, and shipping, and merchants can configure these discounts using your Remix app's UI.
Run this command to scaffold your Discount Function:
Terminal
Anchor to Configure the Discount FunctionConfigure the Discount Function
In this step, you'll configure the Discount Function to apply discounts to products, orders, and shipping based on the discount configuration that is stored on the discount instance and its metafield.
Your Function should only return operations for discountClasses
that the discount applies to. For example, if the discount is configured to apply to PRODUCT
and ORDER
, but not SHIPPING
, your Function should only return operations for PRODUCT
and ORDER
.
Anchor to Define the UI paths and input variablesDefine the UI paths and input variables
- Update the UI paths in
shopify.extension.toml
. This property tells the Shopify admin where to find the UI that allows merchants to configure discounts associated with your Discount Function. - Register a metafield variable that your Function will use as a dynamic input. Refer to variables in input queries for more information. In this example, the
collectionIds
property of the metafield object is used as the input variable for the Function.
Anchor to Query the data needed for your Function cart run targetQuery the data needed for your Function cart run target
The cart_lines_discounts_generate_run.graphql
file drives your function logic by querying essential cart data which is used as the input for your Function. This file queries:
- Cart properties to use with the
inAnyCollection
field for determining which collections your Function will target,$collectionIds
are passed to the query as a variable. - The
discountClasses
property to identify which discount classes (PRODUCT, ORDER, SHIPPING) your Function will return discounts for. - Metafield data to retrieve collection IDs and discount percentage values. The metafield is queried by its key and namespace.
The inAnyCollection
field is used to determine whether a product belongs to one of the specified collections. This field is true
when a product variant is associated with the specified set of collections, and false
otherwise. Note that if the collection set is empty, it returns false
.
Anchor to Query the data needed for your Function delivery run targetQuery the data needed for your Function delivery run target
The cart_delivery_options_discounts_generate_run.graphql
file drives your function logic by querying essential delivery data which is used as the input for your Function. This file queries:
- Cart
deliveryGroups
to retrieve the delivery options available to the customer. - The
discountClasses
property to determine whether the SHIPPING discount class is set. - Metafield data to retrieve the discount percentage for delivery options. The metafield is queried by its key and namespace.
Anchor to Create your cart run Function logicCreate your cart run Function logic
Using the input data from the cart_lines_discounts_generate_run.graphql
file, you can create your Function's logic.
In this example, you retrieve the metafield object which contains the cart line and order discount percentages, the collection IDs for which the discount applies and the discountClasses that your discount will apply to. You can then use this data to create your Function's logic.
First, you parse the metafield, then you can conditionally add ProductDiscountsAddOperation and OrderDiscountsAddOperation operations to the return value based on whether the cart line's product is part of a collection that your discount targets, and whether the discountClasses for the discount are set to PRODUCT
or ORDER
.
Anchor to Create your delivery run Function logicCreate your delivery run Function logic
Using the input data from the cart_delivery_options_discounts_generate_run.graphql
file, you can create your Function's logic.
In this example, you retrieve the metafield object which contains the delivery discount percentage. You can then use this data to create your Function's logic.
First, you parse the metafield, then you can conditionally add DeliveryDiscountsAddOperation operations to the return value based on whether the discountClasses for the discount are set to SHIPPING
.
Anchor to Deploy and testDeploy and test
Anchor to Deploy your appDeploy your app
-
Deploy your updated configuration to Shopify:
Terminal
shopify app deploy -
Restart your app development server:
Terminal
shopify app dev -
Open or reinstall your app using the URL provided by Shopify CLI. To preview your extensions, press
p
in the terminal window where you started your app. -
Accept the new access scope permissions in your store.
Anchor to Create a test discountCreate a test discount
- In your Shopify admin, navigate to Discounts.
- To prevent conflicting discounts from activating, deactivate any existing discounts.
- Click Create discount.
- Under your app name, select your discount function.
- Configure the discount with these values:
- Method: Automatic
- Title: Product, Order, Shipping Discount
- DiscountClasses: Select Product, Order, and Shipping
- Product discount percentage: 20
- Order discount percentage: 10
- Shipping discount percentage: 5
- Collection IDs: Select your test collections
- Click Save
Anchor to Test the discountTest the discount
- Open Discounts in your Shopify admin
-
Locate your new cart line, order, and shipping discount
- Now, go to your development store and add products to your cart.
Your cart page displays:
- Product line discounts
- Order subtotal discount
Your checkout page displays:
- Product line discounts
- Order subtotal discount
-
Shipping rate discounts (after entering shipping address)
Anchor to Review the execution of the FunctionReview the execution of the Function
Anchor to Review the Function executionReview the Function execution
-
In the terminal where
shopify app dev
is running, review your Function executions.When testing Functions on development stores, the
dev
output shows Function executions, debug logs you've added, and a link to a local file containing full execution details. -
In a new terminal window, use the Shopify CLI command
app function replay
to replay a Function execution locally. This lets you debug your Function without triggering it again on Shopify.Terminal
shopify app function replay -
Select the Function execution from the top of the list. Press
q
to quit when you are finished debugging.