> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lynq.am/llms.txt
> Use this file to discover all available pages before exploring further.

# Checkout SDK reference

> Public Checkout methods, events, and types.

# Checkout SDK reference

```ts theme={null}
import { Checkout, ConfigError, MountError } from "@lynqpay/checkout-sdk";
```

| Method                                        | Description                                     |
| --------------------------------------------- | ----------------------------------------------- |
| `mount(selectorOrElement)`                    | Mount hosted Checkout.                          |
| `unmount()`                                   | Remove it; the instance may be mounted again.   |
| `destroy()`                                   | Remove Checkout and listeners permanently.      |
| `onReady(handler)`                            | Subscribe to readiness.                         |
| `onValidation(handler)`                       | Subscribe to hosted-form state.                 |
| `onPaymentResult(handler)`                    | Subscribe to merchant-actionable outcomes.      |
| `onCheckoutError(handler)`                    | Subscribe to initialization and loading errors. |
| `on(event, handler)` / `off(event, handler?)` | Advanced event subscription.                    |
| `isMounted()` / `isReady()` / `isValid()`     | Read UI state only.                             |

`ConfigError` is thrown for invalid configuration or server-side construction. `MountError` is thrown when Checkout cannot mount.


## Related topics

- [Checkout SDK](/build/checkout-sdk.md)
- [Release notes](/resources/release-notes.md)
- [API reference](/reference/api.md)
- [Errors and troubleshooting](/reference/errors.md)
- [Payment Intents](/build/payment-intents.md)