diff --git a/src/Prometheus/PushGateway.php b/src/Prometheus/PushGateway.php
index 8b99982..15414af 100644
--- a/src/Prometheus/PushGateway.php
+++ b/src/Prometheus/PushGateway.php
@@ -11,11 +11,21 @@
 
 class PushGateway
 {
+    const ALLOWED_TRANSPORT_METHODS = [
+        'http',
+        'https',
+    ];
+
     /**
      * @var string
      */
     private $address;
 
+    /**
+     * @var string
+     */
+    private $transport;
+
     /**
      * @var ClientInterface
      */
@@ -23,13 +33,20 @@ class PushGateway
 
     /**
      * PushGateway constructor.
-     * @param string $address host:port of the push gateway
+     * @param $address string host:port of the push gateway
      * @param ClientInterface $client
+     * @param $transport string transport method of the push gateway
      */
-    public function __construct($address, ClientInterface $client = null)
+    public function __construct($address, ClientInterface $client = null, $transport = 'http')
     {
         $this->address = $address;
         $this->client = $client ?? new Client();
+
+        if (!in_array($transport, self::ALLOWED_TRANSPORT_METHODS)) {
+            throw new \InvalidArgumentException(\sprintf('Invalid transport "%s"', $transport));
+        }
+
+        $this->transport = $transport;
     }
 
     /**
@@ -42,7 +59,7 @@ public function __construct($address, ClientInterface $client = null)
      */
     public function push(CollectorRegistry $collectorRegistry, string $job, array $groupingKey = []): void
     {
-        $this->doRequest($collectorRegistry, $job, $groupingKey, 'put');
+        $this->doRequest($collectorRegistry, $job, 'put', $groupingKey);
     }
 
     /**
@@ -55,7 +72,7 @@ public function push(CollectorRegistry $collectorRegistry, string $job, array $g
      */
     public function pushAdd(CollectorRegistry $collectorRegistry, string $job, array $groupingKey = []): void
     {
-        $this->doRequest($collectorRegistry, $job, $groupingKey, 'post');
+        $this->doRequest($collectorRegistry, $job, 'post', $groupingKey);
     }
 
     /**
@@ -67,7 +84,7 @@ public function pushAdd(CollectorRegistry $collectorRegistry, string $job, array
      */
     public function delete(string $job, array $groupingKey = []): void
     {
-        $this->doRequest(null, $job, $groupingKey, 'delete');
+        $this->doRequest(null, $job, 'delete', $groupingKey);
     }
 
     /**
@@ -77,13 +94,17 @@ public function delete(string $job, array $groupingKey = []): void
      * @param string $method
      * @throws GuzzleException
      */
-    private function doRequest(CollectorRegistry $collectorRegistry, string $job, array $groupingKey, $method): void
+    private function doRequest(CollectorRegistry $collectorRegistry, string $job, string $method, array $groupingKey = []): void
     {
-        $url = "http://" . $this->address . "/metrics/job/" . $job;
-        if (!empty($groupingKey)) {
-            foreach ($groupingKey as $label => $value) {
-                $url .= "/" . $label . "/" . $value;
-            }
+        $url = \sprintf(
+            "%s://%s/metrics/job/%s",
+            $this->transport,
+            $this->address,
+            $job
+        );
+
+        foreach ($groupingKey as $label => $value) {
+            $url .= "/" . $label . "/" . $value;
         }
 
         $requestOptions = [
diff --git a/tests/Test/BlackBoxPushGatewayTest.php b/tests/Test/BlackBoxPushGatewayTest.php
index b3ad8ac..961f803 100644
--- a/tests/Test/BlackBoxPushGatewayTest.php
+++ b/tests/Test/BlackBoxPushGatewayTest.php
@@ -10,10 +10,17 @@
 
 class BlackBoxPushGatewayTest extends TestCase
 {
+    public function transportProvider()
+    {
+        yield ['http'];
+        yield ['https'];
+    }
+
     /**
+     * @dataProvider transportProvider
      * @test
      */
-    public function pushGatewayShouldWork()
+    public function pushGatewayShouldWork(string $transport)
     {
         $adapter = new APC();
         $registry = new CollectorRegistry($adapter);
@@ -21,11 +28,11 @@ public function pushGatewayShouldWork()
         $counter = $registry->registerCounter('test', 'some_counter', 'it increases', ['type']);
         $counter->incBy(6, ['blue']);
 
-        $pushGateway = new PushGateway('pushgateway:9091');
+        $pushGateway = new PushGateway('pushgateway:9091', null, $transport);
         $pushGateway->push($registry, 'my_job', ['instance' => 'foo']);
 
-        $httpClient = new Client();
-        $metrics = $httpClient->get("http://pushgateway:9091/metrics")->getBody()->getContents();
+        $client = new Client();
+        $metrics = $client->get($transport . "://pushgateway:9091/metrics")->getBody()->getContents();
         $this->assertContains(
             '# HELP test_some_counter it increases
 # TYPE test_some_counter counter
@@ -35,8 +42,8 @@ public function pushGatewayShouldWork()
 
         $pushGateway->delete('my_job', ['instance' => 'foo']);
 
-        $httpClient = new Client();
-        $metrics = $httpClient->get("http://pushgateway:9091/metrics")->getBody()->getContents();
+        $client = new Client();
+        $metrics = $client->get($transport . "://pushgateway:9091/metrics")->getBody()->getContents();
         $this->assertNotContains(
             '# HELP test_some_counter it increases
 # TYPE test_some_counter counter
diff --git a/tests/Test/BlackBoxTest.php b/tests/Test/BlackBoxTest.php
index b4d8a9e..1d12de8 100644
--- a/tests/Test/BlackBoxTest.php
+++ b/tests/Test/BlackBoxTest.php
@@ -18,7 +18,7 @@ class BlackBoxTest extends TestCase
      */
     private $adapter;
 
-    public function setUp()
+    public function setUp(): void
     {
         $this->adapter = getenv('ADAPTER');
         $this->client = new Client(['base_uri' => 'http://nginx:80/']);