WalletConnect Pay via WalletKit - Kotlin - WalletConnect Pay Docs

Documentation Index

Fetch the complete documentation index at: /llms.txt

Use this file to discover all available pages before exploring further.

This documentation covers integrating WalletConnect Pay through WalletKit. 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:

Sample Wallet - Kotlin (WalletKit)

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Requirements

• Min SDK: 23 (Android 6.0)
• WalletKit: 1.6.0+

You also need a WCP ID for your project, obtained from the WalletConnect Dashboard.How to obtain a WCP ID

1. Navigate to the WalletConnect Dashboard.

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

First, add the required repositories to your project’s settings.gradle.kts or root build.gradle.kts:

allprojects {
    repositories {
        mavenCentral()
        maven { url = uri("https://jitpack.io") }
    }
}

Then add WalletKit to your app’s build.gradle.kts using the BOM (Bill of Materials):

releaseImplementation(platform("com.reown:android-bom:BOM_VERSION"))
releaseImplementation("com.reown:android-core")
releaseImplementation("com.reown:walletkit")

WalletConnectPay is automatically included as a dependency of WalletKit.

Check the GitHub releases for the latest BOM version.

Initialization

WalletConnectPay is automatically initialized when you initialize WalletKit. No additional setup is required.

import com.reown.android.Core
import com.reown.android.CoreClient
import com.reown.walletkit.client.WalletKit
import com.reown.walletkit.client.Wallet

// First, initialize CoreClient in your Application class
val projectId = "" // Get Project ID at https://dashboard.walletconnect.com/
val appMetaData = Core.Model.AppMetaData(
    name = "Wallet Name",
    description = "Wallet Description",
    url = "Wallet URL",
    icons = listOf(/* list of icon url strings */),
    redirect = "kotlin-wallet-wc:/request" // Custom Redirect URI
)

CoreClient.initialize(
    projectId = projectId,
    application = this,
    metaData = appMetaData,
)

// Then initialize WalletKit
val initParams = Wallet.Params.Init(core = CoreClient)

WalletKit.initialize(initParams) { error ->
    // Error will be thrown if there's an issue during initialization
}

The Pay SDK is initialized internally with:

• wcpId from your WalletConnect Project ID
• packageName from your application context

For more details on WalletKit initialization, see the WalletKit Usage documentation.

Payment Link Detection

Use WalletKit.Pay.isPaymentLink() to determine if a scanned URI is a payment link or a standard WalletConnect pairing URI:

fun handleScannedUri(uri: String, accounts: List<String>) {
    if (WalletKit.Pay.isPaymentLink(uri)) {
        // Handle as payment - call getPaymentOptions
        WalletKit.Pay.getPaymentOptions(uri, accounts)
    } else {
        // Handle as WalletConnect pairing
        WalletKit.pair(Wallet.Params.Pair(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

Get Payment Options

Retrieve available payment options for a payment link:

import com.reown.walletkit.client.WalletKit
import com.reown.walletkit.client.Wallet

viewModelScope.launch {
    val result = WalletKit.Pay.getPaymentOptions(
        paymentLink = "https://pay.walletconnect.com/pay_xxx",
        accounts = listOf(
            "eip155:1:0xYourAddress",      // Ethereum
            "eip155:8453:0xYourAddress",   // Base
            "eip155:10:0xYourAddress",     // Optimism
            "eip155:137:0xYourAddress",    // Polygon
            "eip155:42161:0xYourAddress"   // Arbitrum
        )
    )

result.onSuccess { response ->
        // Payment metadata
        val paymentId = response.paymentId
        val paymentInfo = response.info  // Merchant info, amount, expiry

// Available payment options
        val options = response.options
        options.forEach { option ->
            println("Option: ${option.id}")
            println("Amount: ${option.amount.value} ${option.amount.unit}")
            println("Account: ${option.account}")
            println("Requires IC: ${option.collectData != null}")
        }
    }.onFailure { error ->
        handleError(error)
    }
}

Collect User Data (If Required)

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 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

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.

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, 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.

// Check per-option data collection requirement after user selects an option
selectedOption.collectData?.let { collectAction ->
    val url = collectAction.url
    if (url != null) {
        // Build prefill URL with known user data
        // Use the "required" list from collectAction.schema to determine which fields to prefill
        val prefillJson = JSONObject().apply {
            put("fullName", "John Doe")
            put("dob", "1990-01-15")
            put("pobAddress", "123 Main St, New York, NY 10001")
        }.toString()
        // Encode prefill as base64url (URL-safe, no padding)
        val prefillBase64 = Base64.encodeToString(
            prefillJson.toByteArray(),
            Base64.NO_WRAP or Base64.URL_SAFE or Base64.NO_PADDING
        )
        val webViewUrl = Uri.parse(url).buildUpon()
            .appendQueryParameter("prefill", prefillBase64)
            // Optional appearance params (see "Form URL parameters"):
            .appendQueryParameter("theme", "dark") // "light" | "dark"
            // themeVariables is a base64url string exported from the Pay Dashboard:
            // .appendQueryParameter("themeVariables", themeVariables)
            .build().toString()

// Show WebView for this specific option and wait for IC_COMPLETE message
        showWebView(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:

Platform-Specific Bridge Names

Get Required Actions

Get the wallet RPC actions needed to complete the payment. Make sure any required data collection has already completed before calling this:

val actionsResult = WalletKit.Pay.getRequiredPaymentActions(
    Wallet.Params.RequiredPaymentActions(
        paymentId = paymentId,
        optionId = selectedOption.id
    )
)

actionsResult.onSuccess { actions ->
    actions.forEach { action ->
        when (action) {
            is Wallet.Model.RequiredAction.WalletRpc -> {
                val rpcAction = action.action
                // rpcAction.chainId - e.g., "eip155:8453"
                // rpcAction.method - e.g., "eth_signTypedData_v4" or "personal_sign"
                // rpcAction.params - JSON string with signing parameters
            }
        }
    }
}.onFailure { error ->
    handleError(error)
}

Sign Actions

Sign each required action using your wallet’s signing implementation:

val signatures = actions.map { action ->
    when (action) {
        is Wallet.Model.RequiredAction.WalletRpc -> {
            val rpc = action.action
            when (rpc.method) {
                "eth_signTypedData_v4" -> signTypedDataV4(rpc.params)
                "personal_sign" -> personalSign(rpc.params)
                "eth_sendTransaction" -> sendTransaction(rpc.params)
                else -> throw UnsupportedOperationException("Unsupported: ${rpc.method}")
            }
        }
    }
}

Signing eth_signTypedData_v4

import org.json.JSONArray
import org.web3j.crypto.ECKeyPair
import org.web3j.crypto.Sign
import org.web3j.crypto.StructuredDataEncoder

fun signTypedDataV4(params: String): String {
    // params is a JSON array: [address, typedData]
    val paramsArray = JSONArray(params)
    val requestedAddress = paramsArray.getString(0)
    val typedData = paramsArray.getString(1)

// Use StructuredDataEncoder for proper EIP-712 hashing
    val encoder = StructuredDataEncoder(typedData)
    val hash = encoder.hashStructuredData()

val keyPair = ECKeyPair.create(privateKeyBytes)
    val signatureData = Sign.signMessage(hash, keyPair, false)

val rHex = signatureData.r.bytesToHex()
    val sHex = signatureData.s.bytesToHex()
    val v = signatureData.v[0].toInt() and 0xff
    val vHex = v.toString(16).padStart(2, '0')

return "0x$rHex$sHex$vHex".lowercase()
}

Confirm Payment

Submit signatures and finalize the payment:

val confirmResult = WalletKit.Pay.confirmPayment(
    Wallet.Params.ConfirmPayment(
        paymentId = paymentId,
        optionId = selectedOption.id,
        signatures = signatures
    )
)

confirmResult.onSuccess { response ->
    when (response.status) {
        Wallet.Model.PaymentStatus.SUCCEEDED -> {
            // Payment completed successfully
        }
        Wallet.Model.PaymentStatus.PROCESSING -> {
            // Payment is being processed
        }
        Wallet.Model.PaymentStatus.FAILED -> {
            // Payment failed
        }
        Wallet.Model.PaymentStatus.EXPIRED -> {
            // Payment expired
        }
        Wallet.Model.PaymentStatus.REQUIRES_ACTION -> {
            // Additional action required
        }
        Wallet.Model.PaymentStatus.CANCELLED -> {
            // Payment cancelled by user
        }
    }
}.onFailure { error ->
    handleError(error)
}

Data Collection Implementation

When selectedOption.collectData.url is present, display the URL in a WebView. The WebView handles form rendering, validation, and T&C acceptance.

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. See Form URL parameters.

import android.webkit.JavascriptInterface
import android.webkit.WebView
import android.webkit.WebViewClient
import android.webkit.WebResourceRequest
import android.content.Intent
import android.net.Uri
import android.util.Base64
import androidx.compose.runtime.Composable
import androidx.compose.ui.viewinterop.AndroidView
import org.json.JSONObject

@Composable
fun PayDataCollectionWebView(
    url: String,
    onComplete: () -> Unit,
    onError: (String) -> Unit
) {
    AndroidView(factory = { context ->
        WebView(context).apply {
            settings.javaScriptEnabled = true
            settings.domStorageEnabled = true
            settings.allowFileAccess = false

addJavascriptInterface(
                object {
                    @JavascriptInterface
                    fun onDataCollectionComplete(json: String) {
                        val message = JSONObject(json)
                        when (message.optString("type")) {
                            "IC_COMPLETE" -> onComplete()
                            "IC_ERROR" -> onError(
                                message.optString("error", "Unknown error")
                            )
                        }
                    }
                },
                "AndroidWallet"
            )

webViewClient = object : WebViewClient() {
                override fun shouldOverrideUrlLoading(
                    view: WebView?,
                    request: WebResourceRequest?
                ): Boolean {
                    val requestUrl = request?.url?.toString() ?: return false
                    if (!requestUrl.contains("pay.walletconnect.com")) {
                        context.startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(requestUrl)))
                        return true
                    }
                    return false
                }
            }

loadUrl(url)
        }
    })
}

Complete Example

Here’s a complete implementation example:

import com.reown.walletkit.client.WalletKit
import com.reown.walletkit.client.Wallet
import kotlinx.coroutines.launch

class PaymentViewModel : ViewModel() {

fun handleScannedUri(uri: String) {
        if (WalletKit.Pay.isPaymentLink(uri)) {
            processPayment(uri)
        } else {
            // Handle as WalletConnect pairing
            WalletKit.pair(Wallet.Params.Pair(uri))
        }
    }

fun processPayment(paymentLink: String) {
        viewModelScope.launch {
            val walletAddress = "0xYourAddress"

// Step 1: Get payment options
            val optionsResult = WalletKit.Pay.getPaymentOptions(
                paymentLink = paymentLink,
                accounts = listOf(
                    "eip155:1:$walletAddress",
                    "eip155:8453:$walletAddress",
                    "eip155:10:$walletAddress"
                )
            )

optionsResult.onSuccess { response ->
                val paymentId = response.paymentId
                val selectedOption = response.options.first()

// Step 2: Collect data via WebView if required for selected option.
                // IC must happen BEFORE fetching the required actions — the WebView
                // submits the data directly to the backend.
                selectedOption.collectData?.url?.let { webViewUrl ->
                    showDataCollectionWebView(webViewUrl)
                    return@launch // Resume after WebView reports IC_COMPLETE
                }

// Step 3: Get required actions
                val actionsResult = WalletKit.Pay.getRequiredPaymentActions(
                    Wallet.Params.RequiredPaymentActions(
                        paymentId = paymentId,
                        optionId = selectedOption.id
                    )
                )

actionsResult.onSuccess { actions ->
                    // Step 4: Sign actions
                    val signatures = signActions(actions)

// Step 5: Confirm payment
                    val confirmResult = WalletKit.Pay.confirmPayment(
                        Wallet.Params.ConfirmPayment(
                            paymentId = paymentId,
                            optionId = selectedOption.id,
                            signatures = signatures
                        )
                    )

confirmResult.onSuccess { confirmation ->
                        handlePaymentStatus(confirmation.status)
                    }.onFailure { error ->
                        handleError(error)
                    }
                }.onFailure { error ->
                    handleError(error)
                }
            }.onFailure { error ->
                handleError(error)
            }
        }
    }

private suspend fun signActions(
        actions: List<Wallet.Model.RequiredAction>
    ): List<String> {
        return actions.map { action ->
            when (action) {
                is Wallet.Model.RequiredAction.WalletRpc -> {
                    signWithWallet(action.action)
                }
            }
        }
    }

private fun handlePaymentStatus(status: Wallet.Model.PaymentStatus) {
        when (status) {
            Wallet.Model.PaymentStatus.SUCCEEDED -> showSuccess()
            Wallet.Model.PaymentStatus.PROCESSING -> showProcessing()
            Wallet.Model.PaymentStatus.FAILED -> showFailure()
            Wallet.Model.PaymentStatus.EXPIRED -> showExpired()
            Wallet.Model.PaymentStatus.REQUIRES_ACTION -> { /* Handle */ }
            Wallet.Model.PaymentStatus.CANCELLED -> showCancelled()
        }
    }
}

API Reference

WalletKit.Pay The payment operations object within WalletKit.Methods

Parameters Wallet.Params.RequiredPaymentActions

data class RequiredPaymentActions(
    val paymentId: String,
    val optionId: String
)

Wallet.Params.ConfirmPayment

data class ConfirmPayment(
    val paymentId: String,
    val optionId: String,
    val signatures: List<String>
)

Data Models

Wallet.Model.PaymentOptionsResponse

data class PaymentOptionsResponse(
    val paymentId: String,
    val info: PaymentInfo?,
    val options: List<PaymentOption>,
    val collectDataAction: CollectDataAction?,
    val resultInfo: PaymentResultInfo?   // Transaction result details (present when payment already completed)
)

data class PaymentResultInfo(
    val txId: String,                    // Transaction ID
    val optionAmount: PaymentAmount      // Token amount details
)

Wallet.Model.PaymentInfo

data class PaymentInfo(
    val status: PaymentStatus,
    val amount: PaymentAmount,
    val expiresAt: Long,
    val merchant: MerchantInfo
)

data class MerchantInfo(
    val name: String,
    val iconUrl: String?
)

Wallet.Model.PaymentOption

data class PaymentOption(
    val id: String,
    val amount: PaymentAmount,
    val account: String,
    val estimatedTxs: Int?,
    val collectData: CollectDataAction?  // Per-option data collection (null if not required)
)

Wallet.Model.PaymentAmount

data class PaymentAmount(
    val value: String,
    val unit: String,
    val display: PaymentAmountDisplay?
)

data class PaymentAmountDisplay(
    val assetSymbol: String,
    val assetName: String,
    val decimals: Int,
    val iconUrl: String?,
    val networkName: String?,
    val networkIconUrl: String?
)

Wallet.Model.WalletRpcAction

data class WalletRpcAction(
    val chainId: String,   // CAIP-2 chain ID (e.g., "eip155:8453")
    val method: String,    // RPC method (e.g., "eth_signTypedData_v4", "eth_sendTransaction")
    val params: String     // JSON-encoded parameters
)

Wallet.Model.CollectDataAction

data class CollectDataAction(
    val url: String,               // WebView URL for data collection
    val schema: String?            // JSON schema describing required fields
)

Wallet.Model.ConfirmPaymentResponse

data class ConfirmPaymentResponse(
    val status: PaymentStatus,
    val isFinal: Boolean,
    val pollInMs: Long?,
    val info: PaymentResultInfo?      // Transaction result details (present on success)
)

Wallet.Model.PaymentStatus

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 on the selected payment option 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 rather than building native forms. The WebView handles form rendering, validation, and T&C acceptance.
11. Per-Option Data Collection: When displaying payment options, check each option’s collectData field. Show a visual indicator (e.g., “Info required” badge) on options that require data collection. Only open the WebView when the user selects an option with collectData present — use the option’s collectData.url which is already scoped to that option’s account.