diff --git a/pysensorbee/api.py b/pysensorbee/api.py
index d6cc667..3e35e51 100644
--- a/pysensorbee/api.py
+++ b/pysensorbee/api.py
@@ -225,6 +225,12 @@ def close(self, **kwargs):
         """
         self._app.close(**kwargs)
 
+    def is_open(self):
+        """
+        Returns if the connection is established.
+        """
+        return self._open
+
     def get_error(self):
         """
         Returns the last error occurred.
diff --git a/pysensorbee/test/test_api.py b/pysensorbee/test/test_api.py
index e3b9afc..4ece58f 100644
--- a/pysensorbee/test/test_api.py
+++ b/pysensorbee/test/test_api.py
@@ -115,6 +115,9 @@ def test_wsquery(self):
         wsc = api.wsquery(self.TOPOLOGY)
         wsc.start()
         try:
+            # Ensure that the connection is open.
+            self.assertTrue(wsc.is_open())
+
             # One-shot
             wsc._test_oneshot = False
             def callback_1(wsc2, rid, type, payload):