# Payment window

- [Authenticated payment](/docs-en/auth/guide.md): Learn how to integrate authenticated payment through the PG payment window.
- [Definition](/docs-en/auth/guide/def.md): Learn about authenticated payments in Korea.
- [1. Add i'mport library](/docs-en/auth/guide/1..md): Simply by adding the i'mport library, you are half way done with setting up for authenticated payment integration.
- [2. Initialize IMP object](/docs-en/auth/guide/2..md): Prepare for payment integration using the Merchant ID.
- [3. Request payment](/docs-en/auth/guide/3..md): Call a payment window with required parameter values.
- [4. Process payment result](/docs-en/auth/guide/4..md): Securely store the payment results.
- [Iframe method](/docs-en/auth/guide/4./iframe.md): Process the payment result in a typical PC environment using an iframe.
- [Redirect method](/docs-en/auth/guide/4./redirect.md): Process the payment result in a typical mobile environment using page redirection.
- [5. Verify payment information](/docs-en/auth/guide/5..md): Verify the payment information for secure payment service implementation.
- [6. Complete payment](/docs-en/auth/guide/6..md): Complete the payment process by returning the result (success/failure) to the user.
- [Non-authenticated payment](/docs-en/auth/guide-1.md): Learn how to obtain a billing key with the credit card information and integrate immediate/subscription payments.
- [Request billing key payment](/docs-en/auth/guide-1/bill.md): Request a non-authenticated payment request with the credit card information.
- [REST API](/docs-en/auth/guide-1/bill/rest-api.md): Easily get a billing key using the i'mport REST API.
- [PG window](/docs-en/auth/guide-1/bill/pg-window.md): Get a billing key through the payment window provided by the PG.
- [Key-in payment using card info](/docs-en/auth/guide-1/page-1.md): Request payments with only card information without authentication.
- [Subscription payment using billing key](/docs-en/auth/guide-1/subscription-payment-using-billing-key.md): Request subscription (scheduled) payments using the customer\_uid.
- [Payment cancellation (refund)](/docs-en/auth/guide-2.md): Learn how to cancel a payment using the i'mport payment cancel API.
- [Virtual account refund](/docs-en/auth/guide-2/refund.md): Request a refund for a virtual account payment.