Is your device's Token for Push Notifications valid yet? Check it out now!

check_push_token.php

<?php

    class PushMessage {

        private $url = 'https://fcm.googleapis.com/fcm/send';
        private $serverApiKey = "";
        private $devices = array();

        function __construct($apiKeyIn){
            $this->serverApiKey = $apiKeyIn;
        }

        public function setDevices($deviceIds){

            $this->devices = (is_array($deviceIds)) ? $deviceIds : array($deviceIds);

        }

        public function testToken() {

            $device_test = array();

            if (!is_array($this->devices) || count($this->devices) == 0)
                $this->error("No devices set");

            if (strlen($this->serverApiKey) < 8)
                $this->error("Server API Key not set");

            $fields = array(
                'registration_ids' => $this->devices,
                'dry_run' => true
            );

            $headers = array(
                'Authorization: key='.$this->serverApiKey,
                'Content-Type: application/json'
            );

            $curl = curl_init();
            curl_setopt_array($curl, array(
                CURLOPT_URL => $this->url,
                CURLOPT_POST => true,
                CURLOPT_HTTPHEADER => $headers,
                CURLOPT_RETURNTRANSFER => true,
                CURLOPT_POSTFIELDS => json_encode($fields),
                CURLOPT_SSL_VERIFYHOST => false,
                CURLOPT_SSL_VERIFYPEER => false
            ));

            $http_body = curl_exec($curl);
            $http_code = curl_getinfo($curl, CURLINFO_HTTP_CODE);

            curl_close($curl);

            $device_test = array(
                "http_body" => $http_body,
                "http_code" => $http_code
            );

            return $device_test;

        }

        private function error($msg){

            echo "FCM send notification failed with error:";
            echo "\t".$msg;
            exit(1);

        }

    }

    define("API_KEY", ""); //    Your API Key

    $devices = array();

    if (!($fcm_push instanceof PushMessage)) {

        if (class_exists("PushMessage"))
            $fcm_push = new PushMessage(API_KEY);

    }

    $devices[] = ""; //    Token of Device/Devices

    $show_response = true;
    $content_full = "";

    if (!empty($devices)) {

        $fcm_push->setDevices($devices);

        $response_server = $fcm_push->testToken();

        if (!empty($response_server)) {

            $info_resp = $response_server;

            $status_code = json_decode($info_resp['http_code']);

            if ($status_code == 200) {

                $content = json_decode($info_resp['http_body']);

                //$content_full = print_r($content, 1); //  As Object
                $content_full = print_r(json_decode($info_resp['http_body'], 1), 1);    //  As Array

                $tot_devices = count($devices);
                $devices_with_success = $content->success;
                $devices_with_error = $content->failure;

                if (!empty($content->failure)) {

                    for ($i = 0; $i < $tot_devices; $i++) {

                        if (isset($content->results[$i]->error)) {

                            echo "Error with Token: ".$devices[$i]." - Error: ".$content->results[$i]->error."\r\n";

                        }

                    }

                }

            }

        }

    }

    if ($show_response)
        echo $content_full;