> ## Documentation Index
> Fetch the complete documentation index at: https://docs.dintero.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Accept payments online
> Add a checkout to your website or app. Create a session, display the Dintero-hosted payment page, and handle the result.
Add a payment checkout to your website or app. You create a session with the order details, display the Dintero-hosted checkout (embedded or as a redirect), and receive a callback when the customer has paid.
This is the standard integration for any online store or service that needs to collect a one-time payment.
```mermaid theme={null}
sequenceDiagram
participant Merchant as Your server
participant API as Dintero API
participant Checkout as Checkout page
participant Customer as Customer
Merchant->>API: Create checkout session
API-->>Merchant: Session ID + checkout URL
Merchant->>Checkout: Redirect or embed checkout
Customer->>Checkout: Select payment method & pay
Checkout->>API: Payment completed
API->>Merchant: Callback with transaction status
Checkout->>Customer: Redirect to confirmation page
```
## Integration steps
In [Backoffice](https://backoffice.dintero.com/), go to **Settings > API clients** and create a new **Checkout client**. Save the Client ID and Client Secret. The secret is only shown once.
Use your sandbox account (`T` prefix) while developing. Switch to production (`P` prefix) when you're ready to accept real payments.
Exchange your credentials for a bearer token using the OAuth 2.0 client credentials flow. The token is valid for 4 hours and is used in the `Authorization` header for all API calls.
See [Authentication](/docs/checkout/checkout-client#authentication) for details.
Send a `POST` request to `/v1/sessions-profile` with the order details: items, amounts, currency, and URLs for the callback and customer redirect.
The response returns a **session ID** and a **checkout URL** that you use to display the payment page.
See [Create a session](/docs/checkout/create-session) for the full payload reference.
Show the checkout to the customer. You have two options:
* **Redirect**: send the customer to the Dintero-hosted checkout page. Minimal setup, no iframe.
* **Embed**: render the checkout inside your page using the [Web SDK](https://github.com/Dintero/Dintero.Checkout.Web.SDK). More control over the experience.
See [Embed vs redirect](/docs/checkout/embedVredirect) for a comparison.
After the customer pays, Dintero notifies you through two channels:
| Channel | How | Use for |
| ----------------- | ----------------------------------------------------- | ------------------------------------ |
| **callback\_url** | Server-to-server GET request (retried up to 20 times) | Verify payment and fulfill the order |
| **return\_url** | Customer browser redirect (not guaranteed) | Show a confirmation page |
Always verify the transaction via the callback. The browser redirect can fail if the customer closes the tab.
See [Handling payment](/docs/checkout/after-payment) for transaction statuses and handling.
After authorization, you can **capture**, **void**, or **refund** transactions through the Transactions API. Most integrations capture when the order is shipped.
See [Transaction management](/docs/checkout/transaction-management) for available operations and the [state diagram](/docs/checkout/transaction-state-diagram) for how transactions move between statuses.
## What's next
End-to-end walkthrough with code examples in cURL, Python, and Node.js.
Test cards and sandbox scenarios for verifying your integration.
Configure which payment methods are shown in the checkout.
Subscribe to real-time transaction events.