diff --git a/dclient/cli.py b/dclient/cli.py
index 26aeb0b..6ba3faa 100644
--- a/dclient/cli.py
+++ b/dclient/cli.py
@@ -2,6 +2,7 @@ import click
 import httpx
 import json
 import pathlib
+from .utils import url_matches_prefix
 
 
 def get_config_dir():
@@ -79,7 +80,7 @@ def query(url, sql, token):
 def _token_for_url_from_auth(url, auth_file):
     auths = _load_auths(auth_file)
     for auth_url, token in auths.items():
-        if url.startswith(auth_url):
+        if url_matches_prefix(url, auth_url):
             return token
 
 
diff --git a/dclient/utils.py b/dclient/utils.py
new file mode 100644
index 0000000..b03df35
--- /dev/null
+++ b/dclient/utils.py
@@ -0,0 +1,30 @@
+from urllib.parse import urlparse
+
+
+def url_matches_prefix(url: str, prefix: str) -> bool:
+    url_parsed = urlparse(url)
+    prefix_parsed = urlparse(prefix)
+
+    if (
+        url_parsed.scheme != prefix_parsed.scheme
+        or url_parsed.netloc != prefix_parsed.netloc
+    ):
+        return False
+
+    if url_parsed.path == prefix_parsed.path:
+        return True
+
+    url_path = url_parsed.path
+
+    # Add '/' to the end of the paths if they don't already end with '/'
+    prefix_path = prefix_parsed.path
+
+    # Special treatment for /foo.json
+    if url_path.endswith(".json"):
+        if prefix_path + ".json" == url_path:
+            return True
+
+    if not prefix_path.endswith("/"):
+        prefix_path += "/"
+
+    return url_path.startswith(prefix_path)
diff --git a/tests/test_utils.py b/tests/test_utils.py
new file mode 100644
index 0000000..2219a0b
--- /dev/null
+++ b/tests/test_utils.py
@@ -0,0 +1,41 @@
+from dclient.utils import url_matches_prefix
+import pytest
+
+
+@pytest.mark.parametrize(
+    "url,prefix_url,expected",
+    (
+        ("https://example.com/foo/bar", "https://example.com/foo", True),
+        ("https://example.com/foo/bar2", "https://example.com/foo/bar", False),
+        ("https://example.com/foo/bar/baz", "https://example.com/foo/bar", True),
+        ("https://example.com/foo/bar/baz", "https://example.com/foo", True),
+        ("https://example.com/foo.json", "https://example.com/foo", True),
+        # different scheme
+        (
+            "http://example.com/foo/bar",
+            "https://example.com/foo",
+            False,
+        ),
+        # different netloc
+        (
+            "https://example.org/foo/bar",
+            "https://example.com/foo",
+            False,
+        ),
+        # exactly the same
+        ("https://example.com/foo", "https://example.com/foo", True),
+        # trailing '/'
+        (
+            "https://example.com/foo/bar",
+            "https://example.com/foo/bar/",
+            False,
+        ),
+        (
+            "https://example.com/foo/bar/baz",
+            "https://example.com/foo/bar/",
+            True,
+        ),
+    ),
+)
+def test_url_matches_prefix(url, prefix_url, expected):
+    assert url_matches_prefix(url, prefix_url) == expected