# Accept a payment using PAYCO in South Korea

# Direct API


Integrating with [PAYCO](https://www.payco.com/) enables South Korea-based customers to pay using this popular local payment method.

When a customer makes a payment, we redirect them to our local processor partner to authenticate and authorize the payment. After the customer authorizes the payment, we redirect them back to your site.

Use the [Payment Intents API](https://docs.stripe.com/payments/payment-intents.md) to accept payments from South Korean customers using local cards and local payment methods.

## Set up Stripe [Server-side]

First, you need a Stripe account. [Register now](https://dashboard.stripe.com/register).

Use our official libraries for access to the Stripe API from your application:

#### Ruby

```bash
# Available as a gem
sudo gem install stripe
```

```ruby
# If you use bundler, you can add this line to your Gemfile
gem 'stripe'
```

## Create a PaymentIntent [Server-side]

A [PaymentIntent](https://docs.stripe.com/api/payment_intents/object.md) is an object that represents your intent to collect a payment from a customer and tracks the payment process. Create a `PaymentIntent` on your server with the amount and currency. [Enable the payment method](https://dashboard.stripe.com/settings/payment_methods) in your Dashboard. With [dynamic payment methods](https://docs.stripe.com/payments/payment-methods/dynamic-payment-methods.md), Stripe displays eligible payment methods to customers automatically.

```curl
curl https://api.stripe.com/v1/payment_intents \
  -u "<<YOUR_SECRET_KEY>>:" \
  -d amount=10000 \
  -d currency=krw \
  -d "payment_method_data[type]=payco"
```

### Retrieve the client secret

The PaymentIntent includes a *client secret* (The client secret is a unique key returned from Stripe as part of a PaymentIntent. This key lets the client access important fields from the PaymentIntent (status, amount, currency) while hiding sensitive ones (metadata, customer)) that the client side uses to securely complete the payment process. You can use different approaches to pass the client secret to the client side.

#### Single-page application

Retrieve the client secret from an endpoint on your server, using the browser’s `fetch` function. This approach is best if your client side is a single-page application, particularly one built with a modern frontend framework like React. Create the server endpoint that serves the client secret:

#### Ruby

```ruby
get '/secret' do
  intent = # ... Create or retrieve the PaymentIntent
  {client_secret: intent.client_secret}.to_json
end
```

And then fetch the client secret with JavaScript on the client side:

```javascript
(async () => {
  const response = await fetch('/secret');
  const {client_secret: clientSecret} = await response.json();
  // Render the form using the clientSecret
})();
```

#### Server-side rendering

Pass the client secret to the client from your server. This approach works best if your application generates static content on the server before sending it to the browser.

Add the [client_secret](https://docs.stripe.com/api/payment_intents/object.md#payment_intent_object-client_secret) in your checkout form. In your server-side code, retrieve the client secret from the PaymentIntent:

#### Ruby

```erb
<form id="payment-form" data-secret="<%= @intent.client_secret %>">
  <button id="submit">Submit</button>
</form>
```

```ruby
get '/checkout' do
  @intent = # ... Fetch or create the PaymentIntent
  erb :checkout
end
```

## Make sure that your customers understand the terms of use [Client-side]

Stripe’s processor partner requires that customers be made aware of the identity of the processor, and understand its terms of use. You must include the following language and link in your checkout page:

> After submission, you’re redirected to complete next steps. This transaction is processed through NICEPAY in accordance with NICEPAY’s [terms of use](https://start.nicepay.co.kr/homepage/terms/bill.do).

## Redirect to local processor [Client-side]

When a customer clicks to pay with PAYCO, use Stripe.js to submit the payment to Stripe. [Stripe.js](https://docs.stripe.com/payments/elements.md) is the foundational JavaScript library for building payment flows. It automatically handles complexities like the redirect described below, and enables you to extend your integration to other payment methods. Include the Stripe.js script on your checkout page by adding it to the `head` of your HTML file.

```html
<head>
  <title>Checkout</title>
  <script src="https://js.stripe.com/endive/stripe.js"></script>
</head>
```

Create an instance of Stripe.js with the following JavaScript on your checkout page.

```javascript
// Set your publishable key. Remember to change this to your live publishable key in production!
// See your keys here: https://dashboard.stripe.com/apikeys
const stripe = Stripe('<<YOUR_PUBLISHABLE_KEY>>');
```

Use the [client secret](https://docs.stripe.com/api/payment_intents/object.md#payment_intent_object-client_secret) of the `PaymentIntent` and call `stripe.confirmPayment` to handle redirecting to the checkout page of the local processor. On this page, the customer selects their issuer and authorizes the payment. Add a `return_url` to determine where Stripe redirects the customer after they complete the payment.

```javascript
const form = document.getElementById('payment-form');

form.addEventListener('submit', async function(event) {
  event.preventDefault();

  // Set the clientSecret of the PaymentIntent
  const { error } = await stripe.confirmPayment({
    clientSecret: clientSecret,
    confirmParams: {
      payment_method_data: {
        type: 'payco',
      },
      // Return URL where the customer should be redirected after the authorization
      return_url: `${window.location.href}`,
    },
  });

  if (error) {
    // Inform the customer that there was an error.
    const errorElement = document.getElementById('error-message');
    errorElement.textContent = result.error.message;
  }
});
```

The `return_url` corresponds to a page on your website that displays the result of the payment. You can determine what to display by [verifying the status](https://docs.stripe.com/payments/payment-intents/verifying-status.md#checking-status) of the `PaymentIntent`. To verify the status, the Stripe redirect to the `return_url` includes the following URL query parameters. You can also append your own query parameters to the `return_url`. They persist throughout the redirect process.

| Parameter                      | Description                                                                                                                                   |
| ------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------- |
| `payment_intent`               | The unique identifier for the `PaymentIntent`.                                                                                                |
| `payment_intent_client_secret` | The [client secret](https://docs.stripe.com/api/payment_intents/object.md#payment_intent_object-client_secret) of the `PaymentIntent` object. |

## Test integration with PAYCO

Test your integration with PAYCO with your test API keys by viewing the redirect page. You can test a successful payment by authenticating the payment on the redirect page. The PaymentIntent transitions from `requires_action` to `succeeded`. To test authentication failure, use your test API keys and view the redirect page. On the redirect page, click **Fail test payment**. The PaymentIntent transitions from `requires_action` to `requires_payment_method`.

## Optional: Handle post-payment events

Stripe sends a [payment_intent.succeeded](https://docs.stripe.com/api/events/types.md#event_types-payment_intent.succeeded) event when the payment completes. Use the Dashboard, a custom *webhook* (A webhook is a real-time push notification sent to your application as a JSON payload through HTTPS requests), or a partner solution to receive these events and run actions, like sending an order confirmation email to your customer, logging the sale in a database, or starting a shipping workflow.

Listen for these events rather than waiting on a callback from the client. On the client, the customer could close the browser window or quit the app before the callback executes, and malicious clients could manipulate the response. Setting up your integration to listen for asynchronous events also helps you accept more payment methods in the future. Learn about the [differences between all supported payment methods](https://stripe.com/payments/payment-methods-guide).

- **Handle events manually in the Dashboard**

  Use the Dashboard to [view your payments](https://dashboard.stripe.com/payments), send email receipts, handle payouts, or retry failed payments.

- **Build a custom webhook**

  [Build a custom webhook](https://docs.stripe.com/webhooks/handling-payment-events.md#build-your-own-webhook) handler to listen for events and build custom asynchronous payment flows. Test and debug your webhook integration locally with the Stripe CLI.

- **Integrate a prebuilt app**

  Handle common business events, such as [automation](https://stripe.partners/?f_category=automation) or [marketing and sales](https://stripe.partners/?f_category=marketing-and-sales), by integrating a partner application.