<?php
	$ch = curl_init();
	$url = "https://api.smsgatewayapi.com/v1/balance";
	$client_id = "XXX"; // Your API client ID (required)
	$client_secret = "YYY"; // Your API client secret (required)

	curl_setopt($ch, CURLOPT_URL, "$url");
	curl_setopt($ch, CURLOPT_POST, false);
	curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET');
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
	curl_setopt($ch, CURLOPT_VERBOSE, true);
	curl_setopt($ch, CURLOPT_HTTPHEADER, [
		"X-Client-Id: $client_id",
		"X-Client-Secret: $client_secret",
		"Content-Type: application/json",
	]);
	$response = curl_exec($ch);
?>