> ## Documentation Index
> Fetch the complete documentation index at: https://walletconnect-pay-docs-rtomas-improve-docs-sidebar.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# WalletConnect Pay via WalletKit - Flutter
> Integrate WalletConnect Pay through WalletKit for a unified payment experience in your Flutter wallet.
This documentation covers integrating WalletConnect Pay through ReownWalletKit. This approach provides a unified API where Pay is automatically initialized alongside WalletKit, simplifying the integration for wallet developers.
## Sample Wallet
For a complete working example, check out our sample wallet implementation:
A reference Flutter wallet app demonstrating WalletConnect Pay via WalletKit.
**Using AI for Integration?** If you're using an AI IDE or assistant to help with integration, you can provide it with our comprehensive [AI integration prompt](/payments/wallets/walletkit/ai-prompts/flutter) for better context and guidance.
## Requirements
* Flutter 3.0+
* iOS 13.0+
* Android API 23+
* ReownWalletKit
You also need a WCP ID for your project, obtained from the [WalletConnect Dashboard](https://dashboard.walletconnect.com).
**How to obtain a WCP ID**
1. Navigate to the [WalletConnect Dashboard](https://dashboard.walletconnect.com).
2. Select the project that is associated with your wallet (as in, the projectId that is being used for your wallet's WalletConnect integration).
3. Click on the "Get Started" button to get a WCP ID associated with your project.
4. The Dashboard will now show the WCP ID associated with your project.
5. Click on the three dots on the right of the WCP ID and select "Copy WCP ID". You will be using this for your wallet's WalletConnect Pay integration.
## Installation
Add `reown_walletkit` to your `pubspec.yaml`:
```yaml theme={null}
dependencies:
reown_walletkit: ^1.4.0
```
Then run:
```bash theme={null}
flutter pub get
```
WalletConnectPay is automatically included as a dependency of ReownWalletKit.
Check the [pub.dev page](https://pub.dev/packages/reown_walletkit) for the latest version.
## Initialization
The `WalletConnectPay` client is automatically initialized during `ReownWalletKit.init()`. No additional setup is required.
```dart theme={null}
import 'package:reown_walletkit/reown_walletkit.dart';
final walletKit = await ReownWalletKit.createInstance(
projectId: 'YOUR_PROJECT_ID',
metadata: PairingMetadata(
name: 'My Wallet',
description: 'My Wallet App',
url: 'https://mywallet.com',
icons: ['https://mywallet.com/icon.png'],
),
);
```
Access the `WalletConnectPay` client directly via `walletKit.pay`:
```dart theme={null}
final payClient = walletKit.pay;
```
## Payment Link Detection
Detect if a URI is a payment link before processing:
```dart theme={null}
if (walletKit.isPaymentLink(uri)) {
// Handle as payment. See [Get Payment Options] section
} else {
// Handle as regular WalletConnect pairing
await walletKit.pair(uri: Uri.parse(uri));
}
```
## Payment Flow
The payment flow consists of six main steps:
**Detect Payment Link -> Get Options -> Collect Data (if required) -> Get Actions -> Sign Actions -> Confirm Payment**
```mermaid theme={null}
sequenceDiagram
participant User
participant Wallet
participant WebView
participant WalletKit as WalletKit.Pay
participant Backend as WalletConnect Pay
User->>Wallet: Scan QR / Open payment link
Wallet->>WalletKit: isPaymentLink(uri)
WalletKit-->>Wallet: true
Wallet->>WalletKit: getPaymentOptions(request)
WalletKit->>Backend: Fetch payment options
Backend-->>WalletKit: Payment options + merchant info
WalletKit-->>Wallet: PaymentOptionsResponse
Wallet->>User: Display payment options
User->>Wallet: Select payment option
alt Data collection required
Wallet->>WebView: Load collectDataAction.url in WebView
WebView->>User: Display data collection form
User->>WebView: Fill form & accept T&C
WebView-->>Wallet: IC_COMPLETE message
end
Wallet->>WalletKit: getRequiredPaymentActions(request)
WalletKit->>Backend: Get signing actions
Backend-->>WalletKit: Required wallet RPC actions
WalletKit-->>Wallet: List of actions to sign
Wallet->>User: Request signature(s)
User->>Wallet: Approve & sign
Wallet->>WalletKit: confirmPayment(request)
WalletKit->>Backend: Submit payment
Backend-->>WalletKit: Payment status
WalletKit-->>Wallet: ConfirmPaymentResponse
Wallet->>User: Show result
```
Retrieve available payment options for a payment link:
```dart theme={null}
final response = await walletKit.getPaymentOptions(
request: GetPaymentOptionsRequest(
paymentLink: 'https://pay.walletconnect.com/pay_123',
accounts: ['eip155:1:0x...', 'eip155:137:0x...'], // Wallet's CAIP-10 accounts
includePaymentInfo: true,
),
);
print('Payment ID: ${response.paymentId}');
print('Options available: ${response.options.length}');
if (response.info != null) {
print('Amount: ${response.info!.amount.formatAmount()}');
print('Merchant: ${response.info!.merchant.name}');
}
// Check which options require data collection (per-option)
for (final option in response.options) {
if (option.collectData != null) {
print('Option ${option.id} requires info capture');
}
}
```
After the user selects an option, check for `collectData` on it. If present, collect the data **before** fetching the required actions.
## Embedded Data Collection Form
When a payment requires user information (e.g., for Travel Rule compliance), the SDK returns a `collectData` field on individual payment options. Each option may independently require data collection — some options may require it while others don't.
The form is loaded from `selectedOption.collectData.url` and embedded in your wallet (a WebView on mobile, an iframe on web). It handles field rendering, validation, Terms & Conditions and Privacy Policy acceptance, and submits data directly to the backend.
Collect this data **before** fetching the required actions. For an option that requires Information Capture, `getRequiredPaymentActions` fails with `400 IC data required` until the data has been submitted.
### Recommended Flow
The recommended approach is to display all payment options upfront, then handle data collection only when the user selects an option that requires it:
1. Call `getPaymentOptions` and display all available options to the user
2. Show a visual indicator (e.g., "Info required" badge) on options where `option.collectData` is present
3. When the user selects an option, check `selectedOption.collectData`
4. If present, load `selectedOption.collectData.url` in the embedded form
5. Optionally append query parameters to the form URL — `prefill` (known user data), `theme`, and `themeVariables` (appearance). See [Form URL parameters](#form-url-parameters) below. Use proper URL building so existing query parameters are preserved.
6. Listen for completion messages: `IC_COMPLETE` (success) or `IC_ERROR` (failure)
7. On `IC_COMPLETE`, continue the flow — fetch the required actions, sign, and confirm the payment. Don't pass `collectedData` to `confirmPayment()`; the form submits data directly to the backend
### Decision Matrix
| Response `collectData` | `option.collectData` | Behavior |
| ---------------------- | -------------------- | ------------------------------------------------------------------- |
| present | present | Option requires IC — use `option.collectData.url` |
| present | `null` | Option does NOT require IC (others might) — skip IC for this option |
| `null` | `null` | No IC needed for any option |
### Form URL parameters
The form URL accepts the following optional query parameters. Append them to `selectedOption.collectData.url` before loading it, preserving any existing query parameters.
| Parameter | Format | Description |
| ---------------- | ---------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `prefill` | base64url-encoded JSON | Pre-populates known user fields so the user doesn't re-enter them. Keys must match the `required` fields from `collectData.schema` (e.g. `fullName`, `dob`, `pobAddress`). |
| `theme` | `light` or `dark` | Sets the form's base color mode. |
| `themeVariables` | base64url-encoded JSON | Overrides design tokens to match your brand — font, font size, select colors, button border radius, and input border radius. Generate and export this value from the [WalletConnect Pay Dashboard](https://dashboard.walletconnect.com). |
`collectData.schema` is a JSON schema **string** — parse it and read its `required` array to discover the field keys for `prefill`. For example, a `required` array of `["fullName", "dob", "pobAddress"]` maps to a prefill object of `{"fullName": "...", "dob": "...", "pobAddress": "..."}`.
#### Customizing the form appearance
`theme` and `themeVariables` are optional and independent — pass either, both, or neither:
* **`theme`** switches the form between `light` and `dark` base color modes. Match it to your wallet's active mode for a seamless transition.
* **`themeVariables`** applies brand-level overrides (font, font size, select colors, button border radius, and input border radius). Generate the theme in the [WalletConnect Pay Dashboard](https://dashboard.walletconnect.com), export it as a base64url string, and append it to the form URL verbatim — you don't need to encode it at runtime.
The top-level `collectData` on the payment options response is still available for backward compatibility. However, the per-option `collectData` is the recommended approach as it provides more granular control over the flow.
Do **not** pass `collectedData` to `confirmPayment()` when using the embedded form. The form handles data submission directly.
```dart theme={null}
if (selectedOption.collectData?.url != null) {
// Use the "required" list from selectedOption.collectData.schema to determine which fields to prefill
final prefillData = {
'fullName': 'John Doe',
'dob': '1990-01-15',
'pobAddress': '123 Main St, New York, NY 10001',
};
// Encode prefill as base64url (no padding, consistent with the other SDKs)
final prefillBase64 = base64Url.encode(utf8.encode(jsonEncode(prefillData))).replaceAll('=', '');
final uri = Uri.parse(selectedOption.collectData!.url);
final webViewUrl = uri.replace(
queryParameters: {
...uri.queryParameters,
'prefill': prefillBase64,
// Optional appearance params (see "Form URL parameters"):
'theme': 'dark', // "light" | "dark"
// themeVariables is a base64url string exported from the Pay Dashboard:
// 'themeVariables': themeVariables,
},
).toString();
// Show WebView and wait for IC_COMPLETE message
showDataCollectionWebView(webViewUrl);
}
```
### WebView Message Types
The WebView communicates with your wallet through JavaScript bridge messages. The message payload is a JSON string with the following structure:
| Message Type | Payload | Description |
| ------------- | -------------------------------------------- | ------------------------------------------------------------------------- |
| `IC_COMPLETE` | `{ "type": "IC_COMPLETE", "success": true }` | User completed the form successfully. Proceed to payment confirmation. |
| `IC_ERROR` | `{ "type": "IC_ERROR", "error": "..." }` | An error occurred. Display the error message and allow the user to retry. |
**Platform-Specific Bridge Names**
| Platform | Bridge Name | Handler |
| ---------------- | --------------------------------------------- | ------------------------------------------------------------- |
| Kotlin (Android) | `AndroidWallet` | `@JavascriptInterface onDataCollectionComplete(json: String)` |
| Swift (iOS) | `payDataCollectionComplete` | `WKScriptMessageHandler.didReceive(message:)` |
| Flutter | `ReactNativeWebView` (injected via JS bridge) | `JavaScriptChannel.onMessageReceived` |
| React Native | `ReactNativeWebView` (native) | `WebView.onMessage` prop |
Get the required wallet actions for a selected payment option:
```dart theme={null}
final actions = await walletKit.getRequiredPaymentActions(
request: GetRequiredPaymentActionsRequest(
optionId: 'option-id',
paymentId: 'payment-id',
),
);
// Process each action (e.g., sign transactions)
for (final action in actions) {
final walletRpc = action.walletRpc;
print('Chain ID: ${walletRpc.chainId}');
print('Method: ${walletRpc.method}');
// Dispatch based on walletRpc.method — see Sign Actions below
}
```
Sign each action using your wallet's signing implementation, dispatching on the RPC method:
```dart theme={null}
// Sign each action based on its RPC method
final signatures = [];
for (final action in actions) {
final rpc = action.walletRpc;
switch (rpc.method) {
case 'eth_signTypedData_v4':
signatures.add(await signTypedData(rpc.chainId, rpc.params));
break;
case 'eth_sendTransaction':
signatures.add(await sendTransaction(rpc.chainId, rpc.params));
break;
case 'personal_sign':
signatures.add(await personalSign(rpc.chainId, rpc.params));
break;
default:
throw UnimplementedError('Unsupported RPC method: ${rpc.method}');
}
}
```
Payment options may include multiple actions with different RPC methods. For example, a Permit2 payment where the user lacks sufficient allowance returns two actions: an `eth_sendTransaction` to approve the token allowance, followed by an `eth_signTypedData_v4` to sign the Permit2 transfer. Your wallet must check `action.walletRpc.method` and dispatch to the appropriate handler. For full implementation guidance, see [USDT support](/payments/wallets/token-chain-support/usdt-support).
Signatures must be in the same order as the actions array.
Confirm the payment with the collected signatures:
```dart theme={null}
final confirmResponse = await walletKit.confirmPayment(
request: ConfirmPaymentRequest(
paymentId: 'payment-id',
optionId: 'option-id',
signatures: ['0x...', '0x...'], // Signatures from wallet actions
maxPollMs: 60000, // Maximum polling time in milliseconds
),
);
print('Payment Status: ${confirmResponse.status}');
print('Is Final: ${confirmResponse.isFinal}');
```
When using the WebView data-collection approach, you do **not** pass `collectedData` to `confirmPayment`. The WebView submits the collected data directly to the backend during the earlier Collect User Data step.
## Data Collection Implementation
When `selectedOption.collectData.url` is present, display the URL in a WebView using `webview_flutter` (v4.10.0+). Add dependencies:
```yaml theme={null}
dependencies:
webview_flutter: ^4.10.0
url_launcher: ^6.1.0
```
**Data Collection Best Practices**
* **Display prominently**: Show the form full-screen or as a prominent modal so users can interact with it easily
* **Loading indicator**: Show a loading indicator while the form loads
* **Handle errors**: Listen for `IC_ERROR` messages and display a user-facing error message with an option to retry
* **External links**: Open Terms & Conditions and Privacy Policy links in the system browser rather than navigating within the form
* **Domain restriction**: Only allow navigation to WalletConnect pay domains and HTTPS URLs
* **Back navigation**: Handle back/dismiss gracefully — confirm cancellation with the user before closing the form mid-flow
* **Keyboard behavior**: Test that the soft keyboard appears and behaves correctly when users tap on form inputs
* **Theme to match your brand**: Pass `theme=light` or `theme=dark` to match your wallet's active color mode, and apply brand tokens with `themeVariables` exported from the [WalletConnect Pay Dashboard](https://dashboard.walletconnect.com). See [Form URL parameters](#form-url-parameters).
```dart theme={null}
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:webview_flutter/webview_flutter.dart';
import 'package:url_launcher/url_launcher.dart';
class PayDataCollectionWebView extends StatefulWidget {
final String url;
final VoidCallback onComplete;
final ValueChanged onError;
const PayDataCollectionWebView({
super.key,
required this.url,
required this.onComplete,
required this.onError,
});
@override
State createState() =>
_PayDataCollectionWebViewState();
}
class _PayDataCollectionWebViewState extends State {
late final WebViewController _controller;
bool _isLoading = true;
@override
void initState() {
super.initState();
_controller = WebViewController()
..setJavaScriptMode(JavaScriptMode.unrestricted)
..setNavigationDelegate(NavigationDelegate(
onPageFinished: (_) => setState(() => _isLoading = false),
onNavigationRequest: (request) {
if (!request.url.contains('pay.walletconnect.com')) {
launchUrl(Uri.parse(request.url),
mode: LaunchMode.externalApplication);
return NavigationDecision.prevent;
}
return NavigationDecision.navigate;
},
))
..addJavaScriptChannel(
'ReactNativeWebView',
onMessageReceived: (message) {
try {
final data = jsonDecode(message.message) as Map;
switch (data['type']) {
case 'IC_COMPLETE':
widget.onComplete();
break;
case 'IC_ERROR':
widget.onError(data['error'] ?? 'Unknown error');
break;
}
} catch (_) {}
},
)
..loadRequest(Uri.parse(widget.url));
}
@override
Widget build(BuildContext context) {
return Stack(
children: [
WebViewWidget(controller: _controller),
if (_isLoading)
const Center(child: CircularProgressIndicator()),
],
);
}
}
```
## Complete Example
Here's a complete example of processing a payment:
```dart theme={null}
import 'package:reown_walletkit/reown_walletkit.dart';
class PaymentService {
final ReownWalletKit walletKit;
PaymentService(this.walletKit);
/// Process a payment from a payment link (e.g., after scanning QR code)
Future processPayment(String paymentLink) async {
try {
// Step 1: Get payment options
final accounts = await getWalletAccounts(); // Your wallet accounts
final optionsResponse = await walletKit.getPaymentOptions(
request: GetPaymentOptionsRequest(
paymentLink: paymentLink,
accounts: accounts,
includePaymentInfo: true,
),
);
if (optionsResponse.options.isEmpty) {
throw Exception('No payment options available');
}
// Step 2: Select payment option (or let user choose)
PaymentOption selectedOption = optionsResponse.options.first;
final paymentId = optionsResponse.paymentId;
final optionId = selectedOption.id;
// Step 3: Collect data via WebView if required for selected option.
// This must happen BEFORE fetching the required payment actions —
// the backend rejects the actions request with 400 "IC data required"
// for options needing Information Capture if data wasn't collected first.
// The WebView submits the data directly to the backend, so it is NOT
// passed to confirmPayment later.
if (selectedOption.collectData?.url != null) {
await showDataCollectionWebView(selectedOption.collectData!.url);
}
// Step 4: Get required payment actions (if not already in the option)
List actions = selectedOption.actions;
if (actions.isEmpty) {
actions = await walletKit.getRequiredPaymentActions(
request: GetRequiredPaymentActionsRequest(
optionId: optionId,
paymentId: paymentId,
),
);
}
// Step 5: Execute wallet actions and collect signatures
final signatures = [];
for (final action in actions) {
// Dispatch based on action.walletRpc.method:
// 'eth_signTypedData_v4' -> sign EIP-712 typed data
// 'eth_sendTransaction' -> send transaction (e.g., token approval)
// 'personal_sign' -> personal message signing
signatures.add(await signAction(action.walletRpc));
}
// Step 6: Confirm payment
ConfirmPaymentResponse confirmResponse = await walletKit.confirmPayment(
request: ConfirmPaymentRequest(
paymentId: paymentId,
optionId: optionId,
signatures: signatures,
maxPollMs: 60000, // Maximum polling time in milliseconds
),
);
// Step 7: Poll until final status (if needed)
while (!confirmResponse.isFinal && confirmResponse.pollInMs != null) {
await Future.delayed(Duration(milliseconds: confirmResponse.pollInMs!));
confirmResponse = await walletKit.confirmPayment(
request: ConfirmPaymentRequest(
paymentId: paymentId,
optionId: optionId,
signatures: signatures,
maxPollMs: 60000,
),
);
}
// Handle final payment status
switch (confirmResponse.status) {
case PaymentStatus.succeeded:
print('Payment succeeded!');
break;
case PaymentStatus.failed:
throw Exception('Payment failed');
case PaymentStatus.expired:
throw Exception('Payment expired');
case PaymentStatus.cancelled:
throw Exception('Payment cancelled');
case PaymentStatus.requires_action:
throw Exception('Payment requires additional action');
case PaymentStatus.processing:
// Should not happen if isFinal is true
break;
}
} catch (e) {
print('Payment error: $e');
rethrow;
}
}
Future> getWalletAccounts() async {
// Return your wallet's CAIP-10 formatted accounts
// Example: ['eip155:1:0x1234...', 'eip155:137:0x5678...']
return [];
}
}
```
## API Reference
**ReownWalletKit Pay Methods**
| Method | Description |
| -------------------------------------------------------------------------------- | ----------------------------------------------- |
| `isPaymentLink(String uri)` | Check if URI is a payment link |
| `getPaymentOptions({required GetPaymentOptionsRequest request})` | Get available payment options |
| `getRequiredPaymentActions({required GetRequiredPaymentActionsRequest request})` | Get actions requiring signatures |
| `confirmPayment({required ConfirmPaymentRequest request})` | Confirm and finalize payment |
| `pay` | Access the underlying WalletConnectPay instance |
**Models**
**GetPaymentOptionsRequest**
```dart theme={null}
GetPaymentOptionsRequest({
required String paymentLink,
required List accounts,
@Default(false) bool includePaymentInfo,
})
```
**PaymentOptionsResponse**
```dart theme={null}
PaymentOptionsResponse({
required String paymentId,
PaymentInfo? info,
required List options,
CollectDataAction? collectData,
PaymentResultInfo? resultInfo, // Transaction result details (present when payment already completed)
})
```
**PaymentResultInfo**
```dart theme={null}
class PaymentResultInfo {
final String txId; // Transaction ID
final PayAmount optionAmount; // Token amount details
}
```
**PaymentInfo**
```dart theme={null}
PaymentInfo({
required PaymentStatus status,
required PayAmount amount,
required int expiresAt,
required MerchantInfo merchant,
BuyerInfo? buyer,
})
```
**PaymentOption**
```dart theme={null}
PaymentOption({
required String id,
required String account,
required PayAmount amount,
@JsonKey(name: 'etaS') required int etaSeconds,
required List actions,
CollectDataAction? collectData, // Per-option data collection (null if not required)
})
```
**ConfirmPaymentRequest**
```dart theme={null}
ConfirmPaymentRequest({
required String paymentId,
required String optionId,
required List signatures,
int? maxPollMs,
})
```
**ConfirmPaymentResponse**
```dart theme={null}
ConfirmPaymentResponse({
required PaymentStatus status,
required bool isFinal,
int? pollInMs,
PaymentResultInfo? info, // Transaction result details (present on success)
})
```
**PaymentStatus**
```dart theme={null}
enum PaymentStatus {
requires_action,
processing,
succeeded,
failed,
expired,
cancelled,
}
```
**CollectDataAction**
```dart theme={null}
class CollectDataAction {
final String url; // WebView URL for data collection
final String? schema; // JSON schema describing required fields
}
```
## Error Handling
The SDK throws specific exception types for different error scenarios. All errors extend the abstract `PayError` class, which itself extends `PlatformException`:
```dart theme={null}
abstract class PayError extends PlatformException {
PayError({
required super.code,
required super.message,
required super.details,
required super.stacktrace,
});
}
```
| Exception | Description |
| ------------------------- | ------------------------------------ |
| `PayInitializeError` | Initialization failures |
| `GetPaymentOptionsError` | Errors when fetching payment options |
| `GetRequiredActionsError` | Errors when getting required actions |
| `ConfirmPaymentError` | Errors when confirming payment |
All errors include:
* `code`: Error code
* `message`: Error message
* `details`: Additional error details
* `stacktrace`: Stack trace
**Example Error Handling**
```dart theme={null}
try {
final response = await walletKit.getPaymentOptions(request: request);
} on GetPaymentOptionsError catch (e) {
print('Error code: ${e.code}');
print('Error message: ${e.message}');
} on PayError catch (e) {
// Catch any Pay-related error
print('Pay error: ${e.message}');
} catch (e) {
print('Unexpected error: $e');
}
```
## Best Practices
1. **Use WalletKit Integration**: If your wallet already uses WalletKit, prefer this approach for automatic configuration
2. **Use `isPaymentLink()` for Detection**: Use the utility method instead of manual URL parsing for reliable payment link detection
3. **Account Format**: Always use CAIP-10 format for accounts: `eip155:{chainId}:{address}`
4. **Multiple Chains**: Provide accounts for all supported chains to maximize payment options
5. **Signature Order**: Maintain the same order of signatures as the actions array
6. **Error Handling**: Always handle errors gracefully and show appropriate user feedback
7. **Loading States**: Show loading indicators during API calls and signing operations
8. **Expiration**: Check `paymentInfo.expiresAt` and warn users if time is running low
9. **User Data**: Only collect data when `collectData` is present in the response and you don't already have the required user data. If you already have the required data, you can submit this without collecting from the user. You must make sure the user accepts WalletConnect Terms and Conditions and Privacy Policy before submitting user information to WalletConnect.
10. **WebView Data Collection**: When `selectedOption.collectData.url` is present, display the URL in a WebView using `webview_flutter` rather than building native forms. The WebView handles form rendering, validation, and T\&C acceptance.