diff --git a/tests/test_common.py b/tests/test_common.py
new file mode 100644
index 0000000..3879209
--- /dev/null
+++ b/tests/test_common.py
@@ -0,0 +1,29 @@
+# Copyright 2023 Iguazio
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+import unittest
+from v3io.common.helpers import url_join
+
+class Test(unittest.TestCase):
+    def test_url_join(self):
+        self.assertEqual(url_join('a','b') ,       'a/b')    # add one '/' between parts
+        self.assertEqual(url_join('/','a','b') ,   '/a/b')   # limit '/' prefix count to one
+        self.assertEqual(url_join('/','/a','b') ,  '/a/b')   #
+        self.assertEqual(url_join('/','a','/b'),   '/a/b')   #
+        self.assertEqual(url_join('/','/a','/b'),  '/a/b')   #
+        self.assertEqual(url_join('a','b'),        'a/b')    # keep suffix '/' exist/not-exist invariant
+        self.assertEqual(url_join('a','b/'),       'a/b/')   #
+        self.assertEqual(url_join('a','b//'),      'a/b//')  #
+        self.assertEqual(url_join('a','b//', '/'), 'a/b//')  # suffix '/' count may change (we don't care)
+
diff --git a/v3io/common/helpers.py b/v3io/common/helpers.py
index ded4b0c..1be9d2b 100644
--- a/v3io/common/helpers.py
+++ b/v3io/common/helpers.py
@@ -12,13 +12,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-from functools import reduce
-
-
-def _join_slash(left, right):
-    return left.rstrip("/") + "/" + right.lstrip("/")
-
 
 def url_join(*parts):
-    """join parts by pairs with a single slash, leaving left-part leading and right-part trailing slashes."""
-    return reduce(_join_slash, parts) if parts else ""
+    result = ""
+    slash_suffix = False
+    for part_index, part in enumerate(parts):
+        if part == '':
+            continue
+        # add slash prefix before part if:
+        # 1. slash suffix did not exit in prev part
+        # 2. slash prefix does not exit in this part
+        # 3. part is not the first
+        if not slash_suffix and part[0] != '/' and part_index != 0:
+            result += '/' + part
+        else:
+            # if slash suffix existed in prev trim slash prefix from this part
+            result += part if not slash_suffix else part.lstrip("/")
+        slash_suffix = True if part[-1] == '/' else False
+    return result