Full working PHP example

<?php
$httpApiUrl = "https://api.rescuegroups.org/http/v2.json";
$data = array(
	"apikey" => "XXXXXX",
	"objectType" => "animals",
	"objectAction" => "publicSearch",
	"search" => array (
		"calcFoundRows" => "Yes",
		"resultStart" => 0,
		"resultLimit" => 20,
		"resultSort" => "animalID",
		"fields" => array("animalID","animalOrgID","animalName","animalSpecies","animalBreed","animalThumbnailUrl"),
		"filters" => array (
			array(
				"fieldName" => "animalStatus",
				"operation" => "equals",
				"criteria" => "Available"
			)
		)
	)
);
$result = postToApi($data);
if (!$result) {
	echo "login issue with the API.";
	exit;
}
print_r($result);
exit;

function postJson($url, $json) {
	// create a new cURL resource
	$ch = curl_init();
	// set options, url, etc.
	curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type: application/json"));
	curl_setopt($ch, CURLOPT_URL, $url);
	curl_setopt($ch, CURLOPT_POSTFIELDS, $json);
	curl_setopt($ch, CURLOPT_POST, 1);
	//curl_setopt($ch, CURLOPT_VERBOSE, true);
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
	// grab URL and pass it to the browser
	$result = curl_exec($ch);
	if (curl_errno($ch)) {
		// TODO: Handle errors here
		return array(
				"result" => "",
				"status" => "error",
				"error" => curl_error($ch)
		);
	} else {
		// close cURL resource, and free up system resources
		curl_close($ch);
	}
	return array(
			"status" => "ok",
			"error" => "",
			"result" => $result,
	);
}
function postToApi($data) {
	$resultJson = postJson($GLOBALS["httpApiUrl"], json_encode($data));
	if ($resultJson["status"] == "ok") {
		$result = json_decode($resultJson["result"], true);
		$jsonError = getJsonError();
		if (!$jsonError && $resultJson["status"] == "ok") {
			return $result;
		} else {
			return array (
					"status" => "error",
					"text" => $result["error"] . $jsonError,
					"errors" => array()
			);
		}
	} else return false;
}
function getJsonError() {
	switch (json_last_error()) {
		case JSON_ERROR_NONE:
			return false;
			break;
		case JSON_ERROR_DEPTH:
			return "Maximum stack depth exceeded";
			break;
		case JSON_ERROR_STATE_MISMATCH:
			return "Underflow or the modes mismatch";
			break;
		case JSON_ERROR_CTRL_CHAR:
			return "Unexpected control character found";
			break;
		case JSON_ERROR_SYNTAX:
			return "Syntax error, malformed JSON";
			break;
		case JSON_ERROR_UTF8:
			return "Malformed UTF-8 characters, possibly incorrectly encoded";
			break;
		default:
			return "Unknown error";
			break;
	}
}