diff --git a/docs/string/string_validation.rst b/docs/string/string_validation.rst
index 8c5fd79..29596a7 100644
--- a/docs/string/string_validation.rst
+++ b/docs/string/string_validation.rst
@@ -59,3 +59,11 @@ The following functions are used to validate strings.
     >>> val.contains("abc", "d")
     False
 
+:code:`isSlug(input_string)`
+    Returns true if the string contains the substring.
+
+    >>> val.contains("foo-bar")
+    True
+    >>> val.contains("foo bar)
+    False
+
diff --git a/sanatio/main.py b/sanatio/main.py
index 718183f..6ac1662 100644
--- a/sanatio/main.py
+++ b/sanatio/main.py
@@ -20,8 +20,6 @@ def __isvalidString(self, value: str) -> bool:
         if isinstance(value, str):
             return True
 
-        return False
-
     def __isvalidNumber(self, value: int)-> bool:
         """ check if the number is valid or not """
         if value is None:
@@ -30,8 +28,6 @@ def __isvalidNumber(self, value: int)-> bool:
         if isinstance(value, (int, float)):
             return True
 
-        return False
-
     def __isvalidBoolean(self, value: bool)-> bool:
         """ check if the string is boolean or not """
         if value is None:
@@ -40,8 +36,6 @@ def __isvalidBoolean(self, value: bool)-> bool:
         if isinstance(value, bool):
             return True
 
-        return False
-
     def isAadharCard(self, value)-> bool:
         """ check if the string is Aadhar card or not """
         regex = "^[2-9]{1}[0-9]{3}[0-9]{4}[0-9]{4}$"  # need to improve regex for space and hyphen
@@ -55,8 +49,6 @@ def isAadharCard(self, value)-> bool:
                     if checksum_aadhar(value):
                         return True
 
-        return False
-
     def isPostalCode(self, value, locale: str)-> bool:
         """ check if the string is postal code or not """
         country_data = all_country[locale]
@@ -352,7 +344,10 @@ def isPort(self, value: int) -> bool:
 
     def isSlug(self, value: str) -> bool:
         """ check if the string is slug or not """
-        pass
+        regex = "^[a-z0-9-]+$"
+        if re.match(regex, value):
+            return True
+        return False
 
     def isStrongPassword(self, value: str) -> bool:
         """ check if the string is strong password or not
diff --git a/tests/string_case_test.py b/tests/string_case_test.py
index 1786251..3204311 100644
--- a/tests/string_case_test.py
+++ b/tests/string_case_test.py
@@ -58,6 +58,15 @@ def test_isEmpty_false(self):
         self.assertFalse(validator.isEmpty('foo'))
         self.assertFalse(validator.isEmpty(' foo '))
 
+    def test_isSlug_true(self):
+        self.assertTrue(validator.isSlug('foo-bar'))
+        self.assertTrue(validator.isSlug('foo-bar-123'))
+        self.assertTrue(validator.isSlug('foo-bar-123-456'))
+
+    def test_isSlug_false(self):
+        self.assertFalse(validator.isSlug('foo bar'))
+
+
 
 if __name__ == '__main__':
     unittest.main()