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Receive webhook notifications

The webhook feature ensures that you are automatically informed about changes to your BVNK account and minimises the requirement for you to ask for assistance in configuring your required webhook setup.

You can configure real-time notifications via webhooks for key events such as: pay-ins received, payouts sent out, refund initiated, and transaction status changed.

The most significant benefit for you is the ability to automate your workflows by setting up triggers that determine which operations or activities to perform upon receiving a deposit.

For example, if you run a business that issues wallets to customers and these customers make deposits to fund their wallets, you can automatically credit their wallets as soon as you receive the webhook for the successful deposit. This eliminates the need for a manual process of periodically checking the BVNK Portal to confirm deposits.

Create webhooks​

To create a webhook, do the following:

  1. Log in to the BVNK Portal.

  2. On the sidebar, click Integrations, go to the Webhooks tab, and click Add webhook.

  3. In the Add new webhook dialogue, specify the following webhook settings:

    • Description: Provide a short, meaningful description for the webhook.
    • Webhook URL to receive events: Enter the Webhook URL to which the events will be sent.
    • Events to send: Select the events to send from the list provided.

    Here, you can select events for operations related to fiat and crypto.

  4. Click Add.

The new active webhook appears in the list of webhooks. Now you can do the following:

  • List destinations of webhook URLs.
  • Create a destination of webhook URLs.
  • Remove the destination of webhook URLs.
  • List events when creating a destination or viewing details.

Once your payment has been processed, you will receive an asynchronous response (webhook) containing the details of the event to which you subscribed. This response will be sent to the Webhook URL described earlier.

Also, see a product demo or read more in the Help Centre article.

Explore available webhooks​

You can subscribe to the following webhooks depending on your use case:

Event NameTriggered whenRelevant Documentation
PAYMENT WEBHOOKS
bvnk:payment:payin:status-changeStatus of an incoming fiat payment changesSee webhook documentation
bvnk:payment:payout:status-changeStatus of an outgoing fiat payment changesSee webhook documentation
bvnk:payment:transfer:status-changeStatus of an internal payment transfer changesInternal Transfers
CHANNEL WEBHOOKS
bvnk:payment:channel:transaction-on-holdChannel transaction is placed on holdSee channel webhook documentation
bvnk:payment:channel:transaction-detectedChannel transaction is detectedSee channel webhook documentation
bvnk:payment:channel:transaction-confirmedChannel transaction is confirmedSee channel webhook documentation
CRYPTO WEBHOOKS
bvnk:payment:crypto:refund-initiatedCryptocurrency payment refund is initiatedSee crypto webhook documentation
bvnk:payment:crypto:transaction-lateCryptocurrency transaction is marked as lateSee crypto webhook documentation
bvnk:payment:crypto:transaction-settledCryptocurrency transaction is settledSee crypto webhook documentation
bvnk:payment:crypto:status-changeStatus of a cryptocurrency payment changesSee crypto webhook documentation
bvnk:payment:crypto:transaction-on-holdCryptocurrency transaction is placed on holdSee crypto webhook documentation
bvnk:payment:crypto:transaction-confirmedCryptocurrency transaction is confirmedTransaction Confirmation
bvnk:payment:crypto:transaction-detectedCryptocurrency transaction is detectedTransaction Detection
CUSTOMER WEBHOOKS
bvnk:platform:customer:agreement-session-status-changeCustomer agreement session status changesPrepare Customer Agreements
bvnk:platform:customer:status-changeCustomer's status changesCreate a customer via API
bvnk:platform:customer:updateCustomer information is updatedCreate a customer via API
bvnk:platform:customer:document-status-changeCustomer document verification status changesAdd Documents to customers
bvnk:platform:customer:questionnaire-status-changeCustomer questionnaire status changesCustomer Questionnaires
LEDGER WEBHOOKS
bvnk\:ledger:\wallet:createNew wallet is created in the ledgerSee ledger webhook documentation
bvnk:ledger:report:readyLedger report is ready for downloadReceive Transactions Report via Webhook

Create webhook listener​

BVNK sends webhooks for changes on transactions and other entities, so it's a good idea to set up a listener in your service to get the most out of our Payments API.

You can specify your Webhook URL during the creation of a Merchant. To add or change the webhook URL for an existing Merchant, go to the Merchant menu, click Edit, and enter the required address. After you click Save, the Webhook URL will be added along with the generated Secret key.

Click the Merchant's name to see the changes:

Webhooks are sent as an HTTP POST with Content-Type: application/json containing the payload of the object.

Important notes
  • Always check the status of the payment on the API after you receive a webhook, as further details may be required, such as the final amount paid for the transaction about which you have been notified.
  • After you receive the final webhook from BVNK, do not update transactions in your system to prevent duplicate transaction IDs from affecting your customers

Acknowledge events​

BVNK expects the 200 status code upon receipt of a successfully sent webhook.

If your webhook script performs any logic after receiving a webhook, to prevent timeouts, you should return a 200 status code before completing the logic.

Webhook retry policy​

If BVNK does not receive a 200 status code, the webhook retry policy will kick in.

The retry policy adds a delay before each retry, starting with a base delay and increasing the time between retries. The delay grows larger after each attempt, but will not exceed 15 minutes. The system will attempt up to 100 times, and after that, no further retries will occur.

Handle duplicate events​

Callback endpoints might occasionally receive the same event more than once. We advise you to guard against duplicate event receipts. One way to do this is to log the events you've processed and then exclude the logged ones from further processing.

Validate webhooks​

The webhook also contains a signature to allow servers to verify the authenticity of the request using a server-side secret key. The key is displayed in the field Public Key when you create the hook. The signature is present in the headers as the x-signature header.

To calculate the signature, do the following:

  1. Get the payload of the webhook.
  2. Obtain the secret key: go to Manage Account > Manage Merchants, and click a Merchant Name to open its details.
  1. Generate the signature using the Secret Key and payload components. See the examples for different languages below.
Some legacy webhooks may still require concatenation of the following items to create a signature:
  • Webhook URL
  • content-type
  • Webhook payload

Note that these webhooks will be soon discontinued.

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.util.Arrays;


public class Main {

  public static void main(String[] args) throws Exception {
    // Secret key from webhook configuration (used as string directly, not Base64 decoded)
    String secretKey = "JUL5QkQrpZYwW+Kf03QSrb70CG+ea/j8E/JfslENaXhd0AGBDbAtYYP2MdjkYDqiwjBtrtQXsUIbtAf7IGEGfg==";

    // From X-Signature header
    String signatureBase64 = "VWEtiJu/7dLrq0ZtXS0HbGDPy6Re86oZeTnEEc9mlxg=";

    // Compact JSON payload (no spaces/newlines) - this is what the hook service signs
    String payload = "{\"event\":\"bvnk:ledger:report:ready\",\"eventId\":\"0198a8bb-7d56-79ef-92b2-2aed247c21b4\",\"timestamp\":\"2025-08-14T13:18:36.374620938Z\",\"data\":{\"id\":\"8d942264-e27e-44d9-a048-5ed66ac5129f\",\"url\":\"https://bvnk-staging-reports.s3.eu-west-1.amazonaws.com/transaction/8d942264-e27e-44d9-a048-5ed66ac5129f_7b2f87b9-1335-4b1e-bbeb-6a59ba1dc6df.csv?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20250814T131836Z&X-Amz-SignedHeaders=host&X-Amz-Credential=AKIAZP6R7NJUFAGFGMNA%2F20250814%2Feu-west-1%2Fs3%2Faws4_request&X-Amz-Expires=604800&X-Amz-Signature=5c861e552b3e253be28f8e02c818b3c5e00269b9b50b6d4957d5281825d31a67\",\"type\":\"TRANSACTION\",\"status\":\"READY\"}}";

    // Use secret key as UTF-8 bytes directly (as hook service does)
    byte[] secretKeyBytes = secretKey.getBytes("UTF-8");
    SecretKeySpec secretKeySpec = new SecretKeySpec(secretKeyBytes, "HmacSHA256");

    // Initialize HMAC signature verification
    Mac mac = Mac.getInstance("HmacSHA256");
    mac.init(secretKeySpec);

    // Generate signature for the payload
    byte[] computedSignature = mac.doFinal(payload.getBytes());
    String computedSignatureBase64 = java.util.Base64.getEncoder().encodeToString(computedSignature);

    // Decode received signature
    byte[] receivedSignature = java.util.Base64.getDecoder().decode(signatureBase64);

    // Verify signatures match
    boolean verified = Arrays.equals(computedSignature, receivedSignature);

    System.out.println("Expected signature: " + computedSignatureBase64);
    System.out.println("Received signature: " + signatureBase64);
    System.out.println("Signature is valid: " + verified);
  }
}
#!/usr/bin/env python3
"""
BVNK Webhook Signature Verification - Python
This script verifies HMAC-SHA256 signatures from BVNK webhook payloads.
"""

import hmac
import hashlib
import base64

def verify_webhook_signature(secret_key, payload, signature_base64):
    """
    Verify HMAC-SHA256 signature for webhook payload
    
    Args:
        secret_key (str): The shared secret from webhook configuration
        payload (str): The JSON payload as received in webhook
        signature_base64 (str): The signature from X-Signature header
    
    Returns:
        bool: True if signature is valid, False otherwise
    """
    # Convert secret key to bytes using UTF-8 encoding
    secret_bytes = secret_key.encode('utf-8')
    
    # Convert payload to bytes using UTF-8 encoding
    payload_bytes = payload.encode('utf-8')
    
    # Generate HMAC-SHA256 signature
    computed_signature = hmac.new(
        secret_bytes, 
        payload_bytes, 
        hashlib.sha256
    ).digest()
    
    # Base64 encode the computed signature
    computed_signature_base64 = base64.b64encode(computed_signature).decode('ascii')
    
    # Decode the received signature
    received_signature = base64.b64decode(signature_base64)
    
    # Compare signatures using constant-time comparison
    return hmac.compare_digest(computed_signature, received_signature)

def main():
    # Secret key from webhook configuration (used as string directly)
    secret_key = "JUL5QkQrpZYwW+Kf03QSrb70CG+ea/j8E/JfslENaXhd0AGBDbAtYYP2MdjkYDqiwjBtrtQXsUIbtAf7IGEGfg=="
    
    # From X-Signature header
    signature_base64 = "VWEtiJu/7dLrq0ZtXS0HbGDPy6Re86oZeTnEEc9mlxg="
    
    # Compact JSON payload (no spaces/newlines) - this is what the hook service signs
    payload = '{"event":"bvnk:ledger:report:ready","eventId":"0198a8bb-7d56-79ef-92b2-2aed247c21b4","timestamp":"2025-08-14T13:18:36.374620938Z","data":{"id":"8d942264-e27e-44d9-a048-5ed66ac5129f","url":"https://bvnk-staging-reports.s3.eu-west-1.amazonaws.com/transaction/8d942264-e27e-44d9-a048-5ed66ac5129f_7b2f87b9-1335-4b1e-bbeb-6a59ba1dc6df.csv?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20250814T131836Z&X-Amz-SignedHeaders=host&X-Amz-Credential=AKIAZP6R7NJUFAGFGMNA%2F20250814%2Feu-west-1%2Fs3%2Faws4_request&X-Amz-Expires=604800&X-Amz-Signature=5c861e552b3e253be28f8e02c818b3c5e00269b9b50b6d4957d5281825d31a67","type":"TRANSACTION","status":"READY"}}'
    
    # Verify the signature
    is_valid = verify_webhook_signature(secret_key, payload, signature_base64)
    
    # For debugging - compute expected signature
    secret_bytes = secret_key.encode('utf-8')
    payload_bytes = payload.encode('utf-8')
    computed_signature = hmac.new(secret_bytes, payload_bytes, hashlib.sha256).digest()
    expected_signature_base64 = base64.b64encode(computed_signature).decode('ascii')
    
    print(f"Expected signature: {expected_signature_base64}")
    print(f"Received signature: {signature_base64}")
    print(f"Signature is valid: {is_valid}")

if __name__ == "__main__":
    main()
<?php
/**
 * BVNK Webhook Signature Verification - PHP
 * This script verifies HMAC-SHA256 signatures from BVNK webhook payloads.
 */

/**
 * Verify HMAC-SHA256 signature for webhook payload
 * 
 * @param string $secretKey The shared secret from webhook configuration
 * @param string $payload The JSON payload as received in webhook
 * @param string $signatureBase64 The signature from X-Signature header
 * @return bool True if signature is valid, false otherwise
 */
function verifyWebhookSignature($secretKey, $payload, $signatureBase64) {
    // Generate HMAC-SHA256 signature using the secret key as UTF-8 bytes
    $computedSignature = hash_hmac('sha256', $payload, $secretKey, true);
    
    // Base64 encode the computed signature
    $computedSignatureBase64 = base64_encode($computedSignature);
    
    // Decode the received signature
    $receivedSignature = base64_decode($signatureBase64);
    
    // Compare signatures using constant-time comparison
    return hash_equals($computedSignature, $receivedSignature);
}

function main() {
    // Secret key from webhook configuration (used as string directly)
    $secretKey = "JUL5QkQrpZYwW+Kf03QSrb70CG+ea/j8E/JfslENaXhd0AGBDbAtYYP2MdjkYDqiwjBtrtQXsUIbtAf7IGEGfg==";
    
    // From X-Signature header
    $signatureBase64 = "VWEtiJu/7dLrq0ZtXS0HbGDPy6Re86oZeTnEEc9mlxg=";
    
    // Compact JSON payload (no spaces/newlines) - this is what the hook service signs
    $payload = '{"event":"bvnk:ledger:report:ready","eventId":"0198a8bb-7d56-79ef-92b2-2aed247c21b4","timestamp":"2025-08-14T13:18:36.374620938Z","data":{"id":"8d942264-e27e-44d9-a048-5ed66ac5129f","url":"https://bvnk-staging-reports.s3.eu-west-1.amazonaws.com/transaction/8d942264-e27e-44d9-a048-5ed66ac5129f_7b2f87b9-1335-4b1e-bbeb-6a59ba1dc6df.csv?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20250814T131836Z&X-Amz-SignedHeaders=host&X-Amz-Credential=AKIAZP6R7NJUFAGFGMNA%2F20250814%2Feu-west-1%2Fs3%2Faws4_request&X-Amz-Expires=604800&X-Amz-Signature=5c861e552b3e253be28f8e02c818b3c5e00269b9b50b6d4957d5281825d31a67","type":"TRANSACTION","status":"READY"}}';
    
    // Verify the signature
    $isValid = verifyWebhookSignature($secretKey, $payload, $signatureBase64);
    
    // For debugging - compute expected signature
    $computedSignature = hash_hmac('sha256', $payload, $secretKey, true);
    $expectedSignatureBase64 = base64_encode($computedSignature);
    
    echo "Expected signature: " . $expectedSignatureBase64 . "\n";
    echo "Received signature: " . $signatureBase64 . "\n";
    echo "Signature is valid: " . ($isValid ? "true" : "false") . "\n";
}

// Example usage in a webhook handler
function handleWebhook() {
    // Get the payload from POST body
    $payload = file_get_contents('php://input');
    
    // Get the signature from headers
    $signatureBase64 = $_SERVER['HTTP_X_SIGNATURE'] ?? '';
    
    // Your secret key from webhook configuration
    $secretKey = "YOUR_SECRET_KEY_HERE";
    
    // Verify the signature
    if (verifyWebhookSignature($secretKey, $payload, $signatureBase64)) {
        // Signature is valid - process the webhook
        $data = json_decode($payload, true);
        echo "Webhook verified and processed successfully\n";
        // Process your webhook data here
    } else {
        // Invalid signature
        http_response_code(401);
        echo "Invalid webhook signature\n";
    }
}

// Run the test
main();
?>
const crypto = require('crypto');

/**
 * Verify HMAC-SHA256 signature for webhook payload
 * 
 * @param {string} secretKey - The shared secret from webhook configuration
 * @param {string} payload - The JSON payload as received in webhook
 * @param {string} signatureBase64 - The signature from X-Signature header
 * @returns {boolean} True if signature is valid, false otherwise
 */
function verifyWebhookSignature(secretKey, payload, signatureBase64) {
    // Generate HMAC-SHA256 signature using the secret key as UTF-8 bytes
    const computedSignature = crypto
        .createHmac('sha256', secretKey)
        .update(payload, 'utf8')
        .digest();
    
    // Base64 encode the computed signature
    const computedSignatureBase64 = computedSignature.toString('base64');
    
    // Decode the received signature
    const receivedSignature = Buffer.from(signatureBase64, 'base64');
    
    // Compare signatures using constant-time comparison
    return crypto.timingSafeEqual(computedSignature, receivedSignature);
}

function main() {
    // Secret key from webhook configuration (used as string directly)
    const secretKey = "JUL5QkQrpZYwW+Kf03QSrb70CG+ea/j8E/JfslENaXhd0AGBDbAtYYP2MdjkYDqiwjBtrtQXsUIbtAf7IGEGfg==";
    
    // From X-Signature header
    const signatureBase64 = "VWEtiJu/7dLrq0ZtXS0HbGDPy6Re86oZeTnEEc9mlxg=";
    
    // Compact JSON payload (no spaces/newlines) - this is what the hook service signs
    const payload = '{"event":"bvnk:ledger:report:ready","eventId":"0198a8bb-7d56-79ef-92b2-2aed247c21b4","timestamp":"2025-08-14T13:18:36.374620938Z","data":{"id":"8d942264-e27e-44d9-a048-5ed66ac5129f","url":"https://bvnk-staging-reports.s3.eu-west-1.amazonaws.com/transaction/8d942264-e27e-44d9-a048-5ed66ac5129f_7b2f87b9-1335-4b1e-bbeb-6a59ba1dc6df.csv?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20250814T131836Z&X-Amz-SignedHeaders=host&X-Amz-Credential=AKIAZP6R7NJUFAGFGMNA%2F20250814%2Feu-west-1%2Fs3%2Faws4_request&X-Amz-Expires=604800&X-Amz-Signature=5c861e552b3e253be28f8e02c818b3c5e00269b9b50b6d4957d5281825d31a67","type":"TRANSACTION","status":"READY"}}';
    
    // Verify the signature
    const isValid = verifyWebhookSignature(secretKey, payload, signatureBase64);
    
    // For debugging - compute expected signature
    const computedSignature = crypto
        .createHmac('sha256', secretKey)
        .update(payload, 'utf8')
        .digest('base64');
    
    console.log(`Expected signature: ${computedSignature}`);
    console.log(`Received signature: ${signatureBase64}`);
    console.log(`Signature is valid: ${isValid}`);
}

// Example Express.js webhook handler
function setupExpressWebhookHandler(app) {
    const express = require('express');
    
    // Middleware to get raw body for signature verification
    app.use('/webhook', express.raw({ type: 'application/json' }));
    
    app.post('/webhook', (req, res) => {
        const payload = req.body.toString('utf8');
        const signatureBase64 = req.headers['x-signature'];
        
        // Your secret key from webhook configuration
        const secretKey = "YOUR_SECRET_KEY_HERE";
        
        if (verifyWebhookSignature(secretKey, payload, signatureBase64)) {
            // Signature is valid - process the webhook
            const data = JSON.parse(payload);
            console.log('Webhook verified and processed successfully');
            // Process your webhook data here
            res.status(200).send('OK');
        } else {
            // Invalid signature
            console.log('Invalid webhook signature');
            res.status(401).send('Invalid signature');
        }
    });
}

// Browser version (if you need client-side verification - not recommended for security)
async function verifyWebhookSignatureBrowser(secretKey, payload, signatureBase64) {
    // Convert secret key to ArrayBuffer
    const secretKeyBuffer = new TextEncoder().encode(secretKey);
    
    // Import the key for HMAC
    const key = await crypto.subtle.importKey(
        'raw',
        secretKeyBuffer,
        { name: 'HMAC', hash: 'SHA-256' },
        false,
        ['sign', 'verify']
    );
    
    // Convert payload to ArrayBuffer
    const payloadBuffer = new TextEncoder().encode(payload);
    
    // Generate signature
    const signatureBuffer = await crypto.subtle.sign('HMAC', key, payloadBuffer);
    
    // Convert to base64
    const computedSignatureBase64 = btoa(String.fromCharCode(...new Uint8Array(signatureBuffer)));
    
    // Decode received signature
    const receivedSignature = Uint8Array.from(atob(signatureBase64), c => c.charCodeAt(0));
    const computedSignature = new Uint8Array(signatureBuffer);
    
    // Compare signatures
    if (receivedSignature.length !== computedSignature.length) {
        return false;
    }
    
    let result = 0;
    for (let i = 0; i < receivedSignature.length; i++) {
        result |= receivedSignature[i] ^ computedSignature[i];
    }
    
    return result === 0;
}

// Run the test if this file is executed directly
if (require.main === module) {
    main();
}

module.exports = {
    verifyWebhookSignature,
    verifyWebhookSignatureBrowser,
    setupExpressWebhookHandler
};
using System;
using System.Security.Cryptography;
using System.Text;

namespace BvnkWebhookVerification
{
    public class WebhookVerifier
    {
        /// Verify HMAC-SHA256 signature for webhook payload
        public static bool VerifyWebhookSignature(string secretKey, string payload, string signatureBase64)
        {
            try
            {
                // Convert secret key to bytes using UTF-8 encoding
                byte[] secretKeyBytes = Encoding.UTF8.GetBytes(secretKey);
                
                // Convert payload to bytes using UTF-8 encoding
                byte[] payloadBytes = Encoding.UTF8.GetBytes(payload);
                
                // Generate HMAC-SHA256 signature
                using (var hmac = new HMACSHA256(secretKeyBytes))
                {
                    byte[] computedSignature = hmac.ComputeHash(payloadBytes);
                    
                    // Base64 encode the computed signature
                    string computedSignatureBase64 = Convert.ToBase64String(computedSignature);
                    
                    // Decode the received signature
                    byte[] receivedSignature = Convert.FromBase64String(signatureBase64);
                    
                    // Compare signatures using constant-time comparison
                    return CryptographicOperations.FixedTimeEquals(computedSignature, receivedSignature);
                }
            }
            catch (Exception)
            {
                return false;
            }
        }
        
        /// <summary>
        /// Alternative signature verification for older .NET versions without CryptographicOperations
        /// </summary>
        public static bool VerifyWebhookSignatureLegacy(string secretKey, string payload, string signatureBase64)
        {
            try
            {
                byte[] secretKeyBytes = Encoding.UTF8.GetBytes(secretKey);
                byte[] payloadBytes = Encoding.UTF8.GetBytes(payload);
                
                using (var hmac = new HMACSHA256(secretKeyBytes))
                {
                    byte[] computedSignature = hmac.ComputeHash(payloadBytes);
                    string computedSignatureBase64 = Convert.ToBase64String(computedSignature);
                    
                    // Simple string comparison (less secure but works for older .NET)
                    return string.Equals(computedSignatureBase64, signatureBase64, StringComparison.Ordinal);
                }
            }
            catch (Exception)
            {
                return false;
            }
        }
    }
    
    class Program
    {
        static void Main(string[] args)
        {
            // Secret key from webhook configuration (used as string directly)
            string secretKey = "JUL5QkQrpZYwW+Kf03QSrb70CG+ea/j8E/JfslENaXhd0AGBDbAtYYP2MdjkYDqiwjBtrtQXsUIbtAf7IGEGfg==";
            
            // From X-Signature header
            string signatureBase64 = "VWEtiJu/7dLrq0ZtXS0HbGDPy6Re86oZeTnEEc9mlxg=";
            
            // Compact JSON payload (no spaces/newlines) - this is what the hook service signs
            string payload = @"{""event"":""bvnk:ledger:report:ready"",""eventId"":""0198a8bb-7d56-79ef-92b2-2aed247c21b4"",""timestamp"":""2025-08-14T13:18:36.374620938Z"",""data"":{""id"":""8d942264-e27e-44d9-a048-5ed66ac5129f"",""url"":""https://bvnk-staging-reports.s3.eu-west-1.amazonaws.com/transaction/8d942264-e27e-44d9-a048-5ed66ac5129f_7b2f87b9-1335-4b1e-bbeb-6a59ba1dc6df.csv?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20250814T131836Z&X-Amz-SignedHeaders=host&X-Amz-Credential=AKIAZP6R7NJUFAGFGMNA%2F20250814%2Feu-west-1%2Fs3%2Faws4_request&X-Amz-Expires=604800&X-Amz-Signature=5c861e552b3e253be28f8e02c818b3c5e00269b9b50b6d4957d5281825d31a67",""type"":""TRANSACTION"",""status"":""READY""}}";
            
            // Verify the signature
            bool isValid = WebhookVerifier.VerifyWebhookSignature(secretKey, payload, signatureBase64);
            
            // For debugging - compute expected signature
            byte[] secretKeyBytes = Encoding.UTF8.GetBytes(secretKey);
            byte[] payloadBytes = Encoding.UTF8.GetBytes(payload);
            
            using (var hmac = new HMACSHA256(secretKeyBytes))
            {
                byte[] computedSignature = hmac.ComputeHash(payloadBytes);
                string expectedSignatureBase64 = Convert.ToBase64String(computedSignature);
                
                Console.WriteLine($"Expected signature: {expectedSignatureBase64}");
                Console.WriteLine($"Received signature: {signatureBase64}");
                Console.WriteLine($"Signature is valid: {isValid}");
            }
        }
    }
}
require 'openssl'
require 'base64'

class WebhookVerifier
  ##
  # Verify HMAC-SHA256 signature for webhook payload
  #
  # @param secret_key [String] The shared secret from webhook configuration
  # @param payload [String] The JSON payload as received in webhook
  # @param signature_base64 [String] The signature from X-Signature header
  # @return [Boolean] True if signature is valid, false otherwise
  def self.verify_webhook_signature(secret_key, payload, signature_base64)
    # Generate HMAC-SHA256 signature using the secret key as UTF-8 bytes
    computed_signature = OpenSSL::HMAC.digest('SHA256', secret_key, payload)
    
    # Base64 encode the computed signature
    computed_signature_base64 = Base64.strict_encode64(computed_signature)
    
    # Decode the received signature
    received_signature = Base64.strict_decode64(signature_base64)
    
    # Compare signatures using constant-time comparison
    OpenSSL.secure_compare(computed_signature, received_signature)
  rescue StandardError
    false
  end
  
  ##
  # Alternative signature verification for older Ruby versions without secure_compare
  def self.verify_webhook_signature_legacy(secret_key, payload, signature_base64)
    computed_signature = OpenSSL::HMAC.digest('SHA256', secret_key, payload)
    computed_signature_base64 = Base64.strict_encode64(computed_signature)
    
    # Simple string comparison (less secure but works for older Ruby)
    computed_signature_base64 == signature_base64
  rescue StandardError
    false
  end
end

def main
  # Secret key from webhook configuration (used as string directly)
  secret_key = 'JUL5QkQrpZYwW+Kf03QSrb70CG+ea/j8E/JfslENaXhd0AGBDbAtYYP2MdjkYDqiwjBtrtQXsUIbtAf7IGEGfg=='
  
  # From X-Signature header
  signature_base64 = 'VWEtiJu/7dLrq0ZtXS0HbGDPy6Re86oZeTnEEc9mlxg='
  
  # Compact JSON payload (no spaces/newlines) - this is what the hook service signs
  payload = '{"event":"bvnk:ledger:report:ready","eventId":"0198a8bb-7d56-79ef-92b2-2aed247c21b4","timestamp":"2025-08-14T13:18:36.374620938Z","data":{"id":"8d942264-e27e-44d9-a048-5ed66ac5129f","url":"https://bvnk-staging-reports.s3.eu-west-1.amazonaws.com/transaction/8d942264-e27e-44d9-a048-5ed66ac5129f_7b2f87b9-1335-4b1e-bbeb-6a59ba1dc6df.csv?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20250814T131836Z&X-Amz-SignedHeaders=host&X-Amz-Credential=AKIAZP6R7NJUFAGFGMNA%2F20250814%2Feu-west-1%2Fs3%2Faws4_request&X-Amz-Expires=604800&X-Amz-Signature=5c861e552b3e253be28f8e02c818b3c5e00269b9b50b6d4957d5281825d31a67","type":"TRANSACTION","status":"READY"}}'
  
  # Verify the signature
  is_valid = WebhookVerifier.verify_webhook_signature(secret_key, payload, signature_base64)
  
  # For debugging - compute expected signature
  computed_signature = OpenSSL::HMAC.digest('SHA256', secret_key, payload)
  expected_signature_base64 = Base64.strict_encode64(computed_signature)
  
  puts "Expected signature: #{expected_signature_base64}"
  puts "Received signature: #{signature_base64}"
  puts "Signature is valid: #{is_valid}"
end

# Example Sinatra webhook handler
def setup_sinatra_webhook_handler
  require 'sinatra'
  require 'json'
  
  post '/webhook' do
    # Read the raw body
    request.body.rewind
    payload = request.body.read
    
    # Get the signature from headers
    signature_base64 = request.env['HTTP_X_SIGNATURE'] || ''
    
    # Your secret key from webhook configuration
    secret_key = 'YOUR_SECRET_KEY_HERE'
    
    if WebhookVerifier.verify_webhook_signature(secret_key, payload, signature_base64)
      # Signature is valid - process the webhook
      data = JSON.parse(payload)
      puts 'Webhook verified and processed successfully'
      # Process your webhook data here
      status 200
      'OK'
    else
      # Invalid signature
      puts 'Invalid webhook signature'
      status 401
      'Invalid signature'
    end
  end
end

# Example Rails controller
class WebhooksController < ApplicationController
  skip_before_action :verify_authenticity_token
  
  def handle_webhook
    payload = request.raw_post
    signature_base64 = request.headers['X-Signature'] || ''
    
    # Your secret key from webhook configuration
    secret_key = Rails.application.credentials.webhook_secret_key
    
    if WebhookVerifier.verify_webhook_signature(secret_key, payload, signature_base64)
      # Signature is valid - process the webhook
      data = JSON.parse(payload)
      Rails.logger.info 'Webhook verified and processed successfully'
      # Process your webhook data here
      head :ok
    else
      # Invalid signature
      Rails.logger.error 'Invalid webhook signature'
      head :unauthorized
    end
  rescue JSON::ParserError
    Rails.logger.error 'Invalid JSON in webhook payload'
    head :bad_request
  rescue StandardError => e
    Rails.logger.error "Webhook processing error: #{e.message}"
    head :internal_server_error
  end
end

# Run the test if this file is executed directly
main if __FILE__ == $PROGRAM_NAME
Make sure you do not parse your HTTP request into an object and then serialize it.

Instead, provide the webhook raw payload as a string.

The signature will be available in the x-signature header of the webhook. Every new webhook has a unique x-signature header value. Make sure you compare the hash to the correct header.

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