---
title: Checkout
description: >-
  The `authenticate.public.checkout` function ensures that checkout extension
  requests are coming from Shopify, and returns helpers to respond with the
  correct headers.
api_version: v1 latest
api_name: shopify-app-react-router
source_url:
  html: >-
    https://shopify.dev/docs/api/shopify-app-react-router/latest/authenticate/public/checkout
  md: >-
    https://shopify.dev/docs/api/shopify-app-react-router/latest/authenticate/public/checkout.md
---

# Checkout

The `authenticate.public.checkout` function ensures that checkout extension requests are coming from Shopify, and returns helpers to respond with the correct headers.

## authenticate.​public.​checkout(**[request](#authenticatepubliccheckout-propertydetail-request)**​,**[options](#authenticatepubliccheckout-propertydetail-options)**​)

Authenticates requests coming from Shopify checkout extensions.

### Parameters

* **request**

  **Request**

  **required**

* **options**

  **AuthenticateCheckoutOptions**

### Returns

* **Promise\<CheckoutContext>**

### AuthenticateCheckoutOptions

* corsHeaders

  ```ts
  string[]
  ```

### CheckoutContext

Authenticated Context for a checkout request

* cors

  A function that ensures the CORS headers are set correctly for the response.

  ```ts
  EnsureCORSFunction
  ```

* sessionToken

  The decoded and validated session token for the request Refer to the OAuth docs for the \[session token payload]\(https://shopify.dev/docs/apps/auth/oauth/session-tokens#payload).

  ```ts
  JwtPayload
  ```

### EnsureCORSFunction



Examples

### Examples

* #### Authenticate and return offers for the shop

  ##### Description

  Authenticate and return offers for the shop

  ##### /app/routes/\*\*.ts

  ```typescript
  import type {ActionFunctionArgs, LoaderFunctionArgs} from 'react-router';

  import {authenticate} from '../shopify.server';
  import {getOffers} from '../offers.server';

  // The loader responds to preflight requests from Shopify
  export const loader = async ({request}: LoaderFunctionArgs) => {
    await authenticate.public.checkout(request);
  };

  export const action = async ({request}: ActionFunctionArgs) => {
    const {cors, sessionToken} = await authenticate.public.checkout(request);

    const offers = getOffers(sessionToken.dest);
    return cors({offers});
  };
  ```

  ##### /app/offers.server.ts

  ```typescript
  // Most apps would load this from their database
  export function getOffers(shop: string) {
    const offers: Record<any, any[]> = {
      'shop.com': [
        {
          id: '1',
          title: '10% off',
          price: 10,
          type: 'percentage',
        },
        {
          id: '2',
          title: 'Free shipping',
          price: 0,
          type: 'shipping',
        },
      ],
    };

    return offers[shop];
  }
  ```

* #### Setting CORS headers for a public request

  ##### Description

  Use the \`cors\` helper to ensure your app can respond to checkout extension requests.

  ##### app/routes/public/my-route.ts

  ```typescript
  import { LoaderFunctionArgs, json } from "react-router";
  import { authenticate } from "../shopify.server";
  import { getMyAppData } from "~/db/model.server";

  export const loader = async ({ request }: LoaderFunctionArgs) => {
    const { sessionToken, cors } = await authenticate.public.checkout(
      request,
      { corsHeaders: ["X-My-Custom-Header"] }
    );
    const data = await getMyAppData({shop: sessionToken.dest});
    return cors(data));
  };
  ```

* #### Using the decoded session token

  ##### Description

  Get store-specific data using the \`sessionToken\` object.

  ##### app/routes/public/my-route.ts

  ```typescript
  import { LoaderFunctionArgs, json } from "react-router";
  import { authenticate } from "../shopify.server";
  import { getMyAppData } from "~/db/model.server";

  export const loader = async ({ request }: LoaderFunctionArgs) => {
    const { sessionToken } = await authenticate.public.checkout(
      request
    );
    return (await getMyAppData({shop: sessionToken.dest}));
  };
  ```

## Related

[Checkout UI extension API for interacting with session tokens. - Session token API](https://shopify.dev/docs/api/checkout-ui-extensions/latest/apis/session-token)