diff --git a/src/satosa/util.py b/src/satosa/util.py
index b171f1f3e..ea1728853 100644
--- a/src/satosa/util.py
+++ b/src/satosa/util.py
@@ -5,6 +5,7 @@
 import logging
 import random
 import string
+import typing
 
 
 logger = logging.getLogger(__name__)
@@ -91,27 +92,23 @@ def rndstr(size=16, alphabet=""):
     return type(alphabet)().join(rng.choice(alphabet) for _ in range(size))
 
 
-def join_paths(base, *paths):
+def join_paths(*paths, sep: typing.Optional[str] = None) -> str:
     """
-    Joins strings with a "/" separator, like they were path components, but
-    tries to avoid adding an unnecessary separator.  Note that the contents of
-    the strings are not sanitized in any way. If any of the components begins or
-    ends with a "/", the separator is not inserted, and any number of empty
-    strings at the beginning would not add a leading slash.  Any number of empty
-    strings at the end only add a single trailing slash.
-
-    Raises TypeError if any of the components are not strings.
+    Joins strings with a separator like they were path components. The
+    separator is stripped off from all path components, except for the
+    beginning of the first component. Empty (or falsy) components are skipped.
+    Note that the components are not sanitized in any other way.
+
+    Raises TypeError if any of the components are not strings (or empty).
     """
-    sep = "/"
+    sep = sep or "/"
+    leading = ""
+    if paths and paths[0] and paths[0][0] == sep:
+        leading = sep
 
-    path = base
     try:
-        for p in paths:
-            if not path or path.endswith(sep) or p.startswith(sep):
-                path += p
-            else:
-                path += sep + p
+        return leading + sep.join(
+            [path.strip(sep) for path in filter(lambda p: p and p.strip(sep), paths)]
+        )
     except (AttributeError, TypeError) as err:
         raise TypeError("Arguments must be strings") from err
-
-    return path
diff --git a/tests/satosa/test_util.py b/tests/satosa/test_util.py
index 893534b89..e74c9f842 100644
--- a/tests/satosa/test_util.py
+++ b/tests/satosa/test_util.py
@@ -12,23 +12,27 @@
         (["foo", "/bar"], "foo/bar"),
         (["/foo", "baz", "/bar"], "/foo/baz/bar"),
         (["", "foo", "bar"], "foo/bar"),
-        (["", "/foo", "bar"], "/foo/bar"),
-        (["", "/foo/", "bar"], "/foo/bar"),
-        (["", "", "", "/foo", "bar"], "/foo/bar"),
-        (["", "", "/foo/", "", "bar"], "/foo/bar"),
-        (["", "", "/foo/", "", "", "bar/"], "/foo/bar/"),
-        (["/foo", ""], "/foo/"),
-        (["/foo", "", "", ""], "/foo/"),
-        (["/foo//", "bar"], "/foo//bar"),
+        (["", "/foo", "bar"], "foo/bar"),
+        (["", "/foo/", "bar"], "foo/bar"),
+        (["", "", "", "/foo", "bar"], "foo/bar"),
+        (["", "", "/foo/", "", "bar"], "foo/bar"),
+        (["", "", "/foo/", "", "", "bar/"], "foo/bar"),
+        (["/foo", ""], "/foo"),
+        (["/foo", "", "", ""], "/foo"),
+        (["/foo//", "bar"], "/foo/bar"),
         (["foo"], "foo"),
         ([""], ""),
         (["", ""], ""),
         (["'not ", "sanitized'\0/; rm -rf *"], "'not /sanitized'\0/; rm -rf *"),
-        (["foo/", "/bar"], "foo//bar"),
-        (["foo", "", "/bar"], "foo//bar"),
+        (["foo/", "/bar"], "foo/bar"),
+        (["foo", "", "/bar"], "foo/bar"),
         ([b"foo", "bar"], TypeError),
         (["foo", b"bar"], TypeError),
-        ([None, "foo"], TypeError),
+        ([None, "foo"], "foo"),
+        (["foo", [], "bar"], "foo/bar"),
+        (["foo", ["baz"], "bar"], TypeError),
+        (["/", "foo", "bar"], "/foo/bar"),
+        (["///foo", "bar"], "/foo/bar"),
     ],
 )
 def test_join_paths(args, expected):
@@ -37,3 +41,7 @@ def test_join_paths(args, expected):
     else:
         with pytest.raises(expected):
             _ = join_paths(*args)
+
+
+def test_join_paths_with_separator():
+    assert join_paths("this", "is", "not", "a", "path", sep="|") == "this|is|not|a|path"