About the Merchant Callback API
Learn how to connect and communicate with your Merchant Callback API.

The Merchant Callback API is a general endpoint on your ecommerce server that Bolt can use to make synchronous calls and retrieve information. This information includes details on shipping, tax, and viable discounts codes.

How to Connect Bolt to Your Merchant Callback API Endpoint

  1. Log in to your Merchant Dashboard.
  2. Navigate to Administration > API.
  3. Scroll to Merchant Callbacks.
  4. Select Add merchant callback to add a new callback URL (example: www.mystore.com/boltpay/).
  5. To save click Add merchant callback.

Repeat to set up your Merchant Sandbox environment.

API Format & Details

Use our official API Reference to see request and response formats for each API type.

Merchant Callback API Types

  • order.create: Verifies that an order can be created before payment authorization.
  • order.shipping_and_tax: Retrieves shipping and tax options for a given order.
  • discount.code.apply: Applies any discounts entered in the Bolt Checkout.

Request Verification

All requests sent from Bolt to your Merchant Callback API are signed by HMAC to ensure authenticity. You must verify these request signatures using the Signing Secret found in your Merchant Dashboard > Developers > API > Keys.

$hmac_header = $_SERVER['X-Bolt-Hmac-Sha256'];

function verify_webhook($payload, $hmac_header) {
  $computed_hmac = base64_encode(hash_hmac('sha256', $payload, BOLT_SIGNING_SECRET, true));
  return ($computed_hmac == $hmac_header);

Errors & Troubleshooting

To send back specific errors in merchant api responses visit the error codes reference article.

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