Handling callbacks

Collection callback payload

status 2 means paid, 3 means failed. utr is only present on success and may be empty for some channels.

Verify before you trust

Use the raw received values — do not reformat amount or fee. Formatting "1000" into "1000.00" changes the hash and every callback will fail verification.

$data = json_decode(file_get_contents('php://input'), true);

$calc = md5(
  $data['platform_order_no'] .
  $data['merchant_order_no'] .
  $data['amount'] .
  $data['fee'] .
  $data['status'] .
  $key
);

if (!hash_equals($calc, $data['sign'] ?? '')) {
  http_response_code(403);
  exit('SIGN ERROR');
}

// idempotency: platform_order_no is the key
if (alreadyProcessed($data['platform_order_no'])) {
  echo 'SUCCESS';
  exit;
}

if ((int)$data['status'] === 2) {
  markOrderPaid($data['merchant_order_no'], $data['actual_amount'], $data['utr'] ?? '');
}

echo 'SUCCESS';

Rules that prevent most integration bugs

Reply within five seconds. Do the heavy work asynchronously — persist the payload, reply SUCCESS, then process.

Be idempotent. The same order may be delivered more than once; key your writes on platform_order_no.

Never trust the body without the signature. A forged callback that passes your handler is a free order.

Do not rely on callback order. A payout reversal can arrive after a success if it was re-delivered late — always reconcile against the latest state query.

FAQ