diff --git a/docs/source/Login.rst b/docs/source/Login.rst
index c9a3d8c08..66721cde6 100644
--- a/docs/source/Login.rst
+++ b/docs/source/Login.rst
@@ -1,7 +1,22 @@
-Login API
-========================
+Login
+=====
+
+MXCuBE web sessions are meant to expire when there is no activity,
+as opposed to a typical web session that expires when the browser is closed.
+
+So typically a MXCuBE web session closes 1 minute after the browser tab closes.
+After that it is necessary to sign in again.
+
+For this purpose:
+
+* Flask config setting ``PERMANENT_SESSION_LIFETIME`` is set to 60 seconds.
 
+* There is a ``/mxcube/api/v0.1/login/refresh_session`` endpoint
+  that the front end must call regularly (as long as the browser tab is open).
+
+
+Login API
+---------
 
 .. autoflask:: mxcube3.routes.Login:mxcube
     :endpoints: login, signout, loginInfo, get_initial_state, proposal_samples
-
diff --git a/mxcube3/core/components/user/usermanager.py b/mxcube3/core/components/user/usermanager.py
index e6a256794..1c6bf44d6 100644
--- a/mxcube3/core/components/user/usermanager.py
+++ b/mxcube3/core/components/user/usermanager.py
@@ -93,8 +93,7 @@ def update_active_users(self):
                 and _u.last_request_timestamp
                 and (
                     datetime.datetime.now() - _u.last_request_timestamp
-                ).total_seconds()
-                > 60
+                ) > flask.current_app.permanent_session_lifetime
             ):
                 logging.getLogger("HWR.MX3").info(
                     f"Logged out inactive user {_u.username}"
diff --git a/mxcube3/routes/login.py b/mxcube3/routes/login.py
index b93c95a19..d9c0e557f 100644
--- a/mxcube3/routes/login.py
+++ b/mxcube3/routes/login.py
@@ -103,8 +103,10 @@ def send_feedback():
     @bp.route("/refresh_session", methods=["GET"])
     @server.restrict
     def refresh_session():
+        # Since default value of `SESSION_REFRESH_EACH_REQUEST` config setting is `True`
+        # there is no need to do anything to refresh the session.
         logging.getLogger("MX3.HWR").debug("Session refresh")
-        server.flask.permanent_session_lifetime = timedelta(minutes=1)
         app.usermanager.update_active_users()
         return make_response("", 200)
+
     return bp
diff --git a/test/test_authn.py b/test/test_authn.py
index 3552cbd9f..e05d42731 100644
--- a/test/test_authn.py
+++ b/test/test_authn.py
@@ -4,7 +4,9 @@
 """Authentication tests."""
 
 
+import datetime
 import os
+import time
 
 import pytest
 
@@ -15,12 +17,15 @@
 URL_SIGNIN = f"{URL_BASE}/"  # Trailing slash is necessary
 URL_SIGNOUT = f"{URL_BASE}/signout"
 URL_INFO = f"{URL_BASE}/login_info"
+URL_REFRESH = f"{URL_BASE}/refresh_session"
 
 CREDENTIALS_0 = {"proposal": "idtest0", "password": "sUpErSaFe"}
 # Password has to be `wrong` to simulate wrong password in `ISPyBClientMockup`
 CREDENTIALS_0_WRONG = {"proposal": "idtest0", "password": "wrong"}
 CREDENTIALS_1 = {"proposal": "idtest1", "password": "sUpErSaFe"}
 
+SESSION_LIFETIME = 2.0  # seconds
+
 USER_DB_PATH = "/tmp/mxcube-test-user.db"
 
 
@@ -36,6 +41,9 @@ def server():
     argv = []
     server_, _ = mxcube3.build_server_and_config(test=True, argv=argv)
     server_.flask.config["TESTING"] = True
+    # For the tests we override the configured value of the session lifetime
+    # with a much smaller value, so that tests do not need to wait as long.
+    server_.flask.permanent_session_lifetime = SESSION_LIFETIME
 
     yield server_
 
@@ -87,7 +95,6 @@ def test_authn_info(client):
     The login info should have `loggedIn` false before authentication
     and true after successful authentication.
     """
-
     resp = client.get(URL_INFO)
     assert resp.status_code == 200
     assert resp.json["loggedIn"] == False
@@ -140,4 +147,41 @@ def test_authn_different_proposals(make_client):
     assert resp.json["msg"] == "Could not authenticate"
 
 
+def test_authn_session_timeout(client):
+    """Test the session timeout
+
+    The session can be refreshed, and can expire.
+    It should be possible to sign in again after a valid session expired.
+    """
+
+    # Sign in and --as a side effect-- create a session
+    client.post(URL_SIGNIN, json=CREDENTIALS_0)
+    resp = client.get(URL_INFO)
+
+    # Let the session nearly expire
+    time.sleep(SESSION_LIFETIME * 0.9)
+
+    # Refresh the session
+    resp = client.get(URL_REFRESH)
+
+    # Let the session nearly expire again
+    time.sleep(SESSION_LIFETIME * 0.9)
+
+    # Check that the session still has not expired
+    resp = client.get(URL_INFO)
+    assert resp.json["loggedIn"] == True, "Session did not refresh"
+
+    # Let the session expire completely
+    time.sleep(SESSION_LIFETIME * 1.5)
+
+    # Check that the session has expired
+    resp = client.get(URL_INFO)
+    assert resp.json["loggedIn"] == False, "Session did not expire"
+
+    # Check that it is possible to sign in again
+    client.post(URL_SIGNIN, json=CREDENTIALS_0)
+    resp = client.get(URL_INFO)
+    assert resp.json["loggedIn"] == True, "We can not login again"
+
+
 # EOF