medusa-store/docs/content/modules/discounts/storefront/use-discounts-in-checkout.mdx

---
description: 'Learn how to implement discount functionalities in your storefront using the REST APIs. This includes adding a discount to the cart, showing the discount details, and removing the discount from the cart.'
addHowToData: true
---

import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';

# Use Discounts in Checkout

In this document, learn how to use discounts during checkout on the storefront.

:::info

You can check out the [Discounts Architecture documentation](../discounts.md) to learn more about how discounts work.

:::

## Overview

Customers can use discounts during checkout to benefit from promotions that the merchant provides. Discounts are added to a cart using its unique code.

In this document, you’ll learn how to add a discount to a cart, how to display details related to the discount, and how to remove a discount from a cart.

### Scenario

You want to implement discount functionality in your store to allow customers to apply discount codes to their cart and remove them from the cart. You also want to display the discount details for the customer.

---

## Prerequisites

### Medusa Components

It's assumed that you already have a Medusa backend installed and set up. If not, you can follow the [quickstart guide](../../../development/backend/install.mdx) to get started.

It is also assumed you already have a storefront set up. It can be a custom storefront or one of Medusa’s storefronts. If you don’t have a storefront set up, you can install the [Next.js starter storefront](../../../starters/nextjs-medusa-starter.mdx).

### JS Client

This guide includes code snippets to send requests to your Medusa backend using Medusa’s JS Client, among other methods.

If you follow the JS Client code blocks, it’s assumed you already have [Medusa’s JS Client installed](../../../js-client/overview.md) and have [created an instance of the client](../../../js-client/overview.md#configuration).

### Medusa React

This guide also includes code snippets to send requests to your Medusa backend using Medusa React, among other methods.

If you follow the Medusa React code blocks, it's assumed you already have [Medusa React installed](../../../medusa-react/overview.md) and have [used MedusaProvider higher in your component tree](../../../medusa-react/overview.md#usage).

It's also assumed you already have [used CartProvider higher in your component tree](../../../medusa-react/overview.md#cartprovider).

### Previous Steps

This document assumes you’ve already taken care of the add-to-cart flow. So, you should have a [cart created](/api/store/#tag/Cart/operation/PostCart) for the customer with at least [one product in it](/api/store/#tag/Cart/operation/PostCartsCartLineItems).

You can learn how to implement the cart flow using [this documentation](../../../modules/carts-and-checkout/storefront/implement-cart.mdx).

---

## Add Discount to Cart

The customer can enter a discount code during the checkout flow to benefit from a promotion.

You can add a discount to a customer’s cart by sending the [Update Cart request](/api/store/#tag/Cart/operation/PostCartsCart):

<Tabs groupId="request-type" isCodeTabs={true}>
<TabItem value="client" label="Medusa JS Client" default>

```ts
medusa.carts.update(cartId, {
  discounts: [
    {
      code,
    },
  ],
})
.then(({ cart }) => {
  console.log(cart.discounts)
})
.catch((e) => {
  // display an error to the customer
  alert("Discount is invalid")
})
```

</TabItem>
<TabItem value="medusa-react" label="Medusa React">

```tsx
import { useCart } from "medusa-react"

const Cart = () => {
  // ...

  const { updateCart } = useCart()

  const addDiscount = (code: string) => {
    updateCart.mutate({
      discounts: [
        {
          code,
        },
      ],
    })
  }

  // ...
}

export default Cart
```

</TabItem>
<TabItem value="fetch" label="Fetch API">

```ts
fetch(`<BACKEND_URL>/store/carts/${cartId}`, {
  method: "POST",
  credentials: "include",
  body: JSON.stringify({
    discounts: [
      {
        code,
      },
    ],
  }),
  headers: {
    "Content-Type": "application/json",
  },
})
.then((response) => response.json())
.then(({ cart }) => {
  console.log(cart.discounts)
})
.catch((e) => {
  // display an error to the customer
  alert("Discount is invalid")
})
```

</TabItem>
</Tabs>

This request requires the customer’s cart ID as a path parameter. In the body of the request, you can update many cart-related details, including adding discounts by passing the `discounts` field. It is an array of objects, with each object having a property `code` with its value being the discount’s unique code.

:::info

Customers can add more than one discount to their cart, however, only one non-free shipping discount is allowed per cart.

:::

If the discount is applied successfully, the entire cart object will be returned. You can access the discounts applied on the cart in the `cart.discounts` array.

In case the customer enters an invalid discount or the discount cannot be applied to the cart because it doesn’t meet its conditions, the request will return an error. You can handle the error in the `catch` method.

---

## Display Discount Details

After the customer enters a discount code and it is applied to the cart, you can display the discount details to the customer. This shows the customer how much they benefitted from the discount.

The previous request returns the full cart object with different fields that can be used to display the discount details depending on the discount type.

### Display Discount Information

In the returned `cart` object, all discounts applied can be found in the `discounts` array. The following properties can be used to display the discount information:

```json
{
  "discounts": [
    {
      "code": "TEST",
      "is_dynamic": false,
      "starts_at": "2022-12-01T15:09:21.149Z",
			"ends_at": null,
      "usage_limit": null,
      "usage_count": 0,
      "rule": {
          "description": "percentage discount",
          "type": "percentage",
          "value": 20,
          "allocation": "total",
          "conditions": [
            //...
          ],
          //...
      },
      //...
    }
  ],
  //...
}
```

- The `code` property is the code of the discount. This is the code that the customer enters to apply the discount.
- The `starts_at` and `ends_at` indicate the start and expiry dates of the discount. If there’s no end date, the `ends_at` property will be null.
- The `usage_limit` property indicates if there is any usage limit set on the discount. The `usage_count` property indicates how many times this discount has been used.
- The `rule` property includes details related to the type of discount, its value, and its conditions if there are any.

### Display Item Discounts

In the returned `cart` object, the property `items` is an array of items in the cart. If a discount is applied to an item, the following properties inside the item can be used to get the item-specific discount details:

```json
{
  "items": [
    {
      "adjustments": [
        {
          "description": "discount",
          "discount_id": "disc_01GK73RBCRXXT8HWEYMQE4RCY6",
          "amount": 730,
          //...
        }
      ],
      "subtotal": 3650,
      "discount_total": 730,
      "total": 2920,
      //...
    }
  ]
}
```

- The `adjustments` property is an array of objects, each containing details about the adjustment made to the item. Discounts applied to the item will be represented by an adjustment in this array. It will have the `description` property with the value `discount`, the `discount_id` property, and the `amount` of the discount.
- The `subtotal` property is the price before the discounts are applied.
- The `discount_total` property is the sum of all discount amounts.
- The `total` property is the total of the item after applying the discounts.

### Display Cart Discounts

The returned `cart` object has the following properties that can be used to display cart’s general discount details:

```json
{
  "subtotal": 11550,
  "discount_total": 1910,
  "shipping_total": 0,
  "total": 9640,
  //...
}
```

- The `subtotal` property is the total of the cart before applying any discount.
- The `discount_total` property is the total discount amounts applied to the cart.
- The `shipping_total` property is the total shipping amount. If a Free Shipping discount is applied to the cart, `shipping_total` and `discount_total` will be 0.
- The `total` property is the total amount of the cart after applying the discount.

---

## Remove Discount from Cart

The customer can choose to remove a discount from their cart.

You can remove a discount from a customer’s cart using the [Remove Discount request](/api/store/#tag/Cart/operation/DeleteCartsCartDiscountsDiscount):

<Tabs groupId="request-type" isCodeTabs={true}>
<TabItem value="client" label="Medusa JS Client" default>

```ts
medusa.carts.deleteDiscount(cartId, code)
.then(({ cart }) => {
  console.log(cart.discounts)
})
```

</TabItem>
<TabItem value="fetch" label="Fetch API">

```ts
fetch(`<BACKEND_URL>/store/carts/${cartId}/discounts/${code}`, {
  method: "DELETE",
  credentials: "include",
})
.then((response) => response.json())
.then(({ cart }) => {
  console.log(cart.discounts)
})
```

</TabItem>
</Tabs>

This request accepts the cart ID and the code of the discount to remove. If the discount is removed successfully, the request returns the updated cart object, where you won’t find the discount in the `discounts` array anymore.

The totals of the cart and its items will be updated as well.