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

# Get Started

> Installation and setup for the Flutter SDK reference for Crossmint checkout

The Crossmint Flutter SDK (`crossmint_flutter`) provides an embedded checkout widget for integrating Crossmint checkout into your Flutter application. It supports fiat (credit card, Apple Pay, Google Pay) and crypto payment methods.

***

## Quick Start

Install the SDK and add the embedded checkout widget to your Flutter app.

### Usage

```dart checkout_screen.dart theme={null}
import 'package:crossmint_flutter/crossmint_flutter_ui.dart';

class CheckoutScreen extends StatefulWidget {
  const CheckoutScreen({super.key});

  @override
  State<CheckoutScreen> createState() => _CheckoutScreenState();
}

class _CheckoutScreenState extends State<CheckoutScreen> {
  final _controller = CrossmintCheckoutController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CrossmintEmbeddedCheckout(
        apiKey: 'YOUR_CLIENT_API_KEY',
        config: CrossmintCheckoutConfig(
          order: CrossmintCheckoutNewOrder.typed(
            lineItems: [
              CrossmintCheckoutLineItem.collection(
                collectionLocator: 'crossmint:YOUR_COLLECTION_ID',
              ),
            ],
          ),
          payment: CrossmintCheckoutPayment(
            fiat: CrossmintCheckoutFiatPayment(enabled: true),
            crypto: CrossmintCheckoutCryptoPayment(enabled: true),
          ),
        ),
        checkoutController: _controller,
        onOrderUpdated: (order) {
          debugPrint('Order updated: ${order['status']}');
        },
      ),
    );
  }
}
```