diff --git a/yubihsm/backends/http.py b/yubihsm/backends/http.py
index 80de3ea..e413bab 100644
--- a/yubihsm/backends/http.py
+++ b/yubihsm/backends/http.py
@@ -34,12 +34,17 @@ def __init__(
         By default, the backend will attempt to connect to a connector running
         locally, on the default port.
 
-        :param str url: (optional) The URL to connect to.
+        :param str url: (optional) The URL (scheme & domain or full path) to
+            connect to.
         :param timeout: (optional) A timeout in seconds, or a tuple of two
             values to use as connection timeout and request timeout.
         :type timeout: int or tuple[int, int]
         """
-        self._url = parse.urljoin(url, "connector/api")
+
+        if not parse.urlparse(url).path:
+            self._url = parse.urljoin(url, "connector/api")
+        else:
+            self._url = url
         self._timeout = timeout
 
         self._session = requests.Session()