PHP SDK

composer require pawpayments/sdk

use PawPayments\Sdk\PawPaymentsClient;
use PawPayments\Sdk\Exception\PawPaymentsApiException;

$client = new PawPaymentsClient(
    apiKey:  getenv('PAW_API_KEY'),
    baseUrl: 'https://api.pawpayments.com', // default
);

try {
    $invoice = $client->createInvoice([
        'fiat'         => 'USD',
        'fiat_amount'  => '25.00',
        'billing_type' => 'STATIC',
        'extra'        => 'order-1042',
        'notify_url'   => 'https://example.com/webhooks/paw',
        'metadata'     => ['source' => 'custom-app', 'flow' => 'checkout'],
    ]);

    header('Location: ' . $invoice['payment_url']);
} catch (PawPaymentsApiException $e) {
    error_log('Paw API error: ' . $e->getCode() . ' ' . $e->getMessage());
}

use PawPayments\Sdk\Webhook;

$raw     = file_get_contents('php://input');
$sigHdr  = $_SERVER['HTTP_X_PAW_SIGNATURE'] ?? '';
$payload = json_decode($raw, true) ?: [];

if (!Webhook::verify($raw, $sigHdr, $payload, $apiKey)) {
    http_response_code(401);
    echo 'Invalid signature';
    return;
}

if (!empty($payload['permanent_address_id'])) {
    http_response_code(200);
    echo 'OK';
    return;
}

// Process $payload['order_id'], $payload['status'], $payload['fiat_amount']…