diff --git a/swh/web/assets/src/bundles/webapp/webapp.css b/swh/web/assets/src/bundles/webapp/webapp.css
--- a/swh/web/assets/src/bundles/webapp/webapp.css
+++ b/swh/web/assets/src/bundles/webapp/webapp.css
@@ -675,3 +675,27 @@
 .sidebar-collapse .swh-search-navbar {
     right: 4rem;
 }
+
+.swh-corner-ribbon {
+    width: 200px;
+    background: #fecd1b;
+    color: #e20026;
+    position: absolute;
+    text-align: center;
+    line-height: 50px;
+    letter-spacing: 1px;
+    box-shadow: 0 0 3px rgba(0, 0, 0, 0.3);
+    top: 55px;
+    right: -50px;
+    left: auto;
+    transform: rotate(45deg);
+    z-index: 2000;
+}
+
+@media screen and (max-width: 600px) {
+    .swh-corner-ribbon {
+        line-height: 30px;
+        top: 53px;
+        right: -65px;
+    }
+}
diff --git a/swh/web/common/utils.py b/swh/web/common/utils.py
--- a/swh/web/common/utils.py
+++ b/swh/web/common/utils.py
@@ -256,6 +256,7 @@
         # To avoid django.template.base.VariableDoesNotExist errors
         # when rendering templates when standard Django user is logged in.
         request.user.backend = "django.contrib.auth.backends.ModelBackend"
+    site_base_url = request.build_absolute_uri("/")
     return {
         "swh_object_icons": swh_object_icons,
         "available_languages": None,
@@ -263,9 +264,15 @@
         "oidc_enabled": bool(config["keycloak"]["server_url"]),
         "browsers_supported_image_mimes": browsers_supported_image_mimes,
         "keycloak": config["keycloak"],
-        "site_base_url": request.build_absolute_uri("/"),
+        "site_base_url": site_base_url,
         "DJANGO_SETTINGS_MODULE": os.environ["DJANGO_SETTINGS_MODULE"],
         "status": config["status"],
+        "swh_web_staging": any(
+            [
+                server_name in site_base_url
+                for server_name in config["staging_server_names"]
+            ]
+        ),
     }
 
 
diff --git a/swh/web/config.py b/swh/web/config.py
--- a/swh/web/config.py
+++ b/swh/web/config.py
@@ -16,6 +16,11 @@
 
 SWH_WEB_INTERNAL_SERVER_NAME = "archive.internal.softwareheritage.org"
 
+STAGING_SERVER_NAMES = [
+    "webapp.staging.swh.network",
+    "webapp.internal.staging.swh.network",
+]
+
 SETTINGS_DIR = os.path.dirname(settings.__file__)
 
 DEFAULT_CONFIG = {
@@ -104,6 +109,7 @@
         },
     ),
     "metadata_search_backend": ("string", "swh-indexer-storage"),  # or "swh-search"
+    "staging_server_names": ("list", STAGING_SERVER_NAMES),
 }
 
 swhweb_config = {}  # type: Dict[str, Any]
diff --git a/swh/web/settings/tests.py b/swh/web/settings/tests.py
--- a/swh/web/settings/tests.py
+++ b/swh/web/settings/tests.py
@@ -104,6 +104,7 @@
     )
 else:
     ALLOWED_HOSTS += ["testserver", SWH_WEB_INTERNAL_SERVER_NAME]
+    ALLOWED_HOSTS += get_config()["staging_server_names"]
 
     # Silent DEBUG output when running unit tests
     LOGGING["handlers"]["console"]["level"] = "INFO"  # type: ignore
diff --git a/swh/web/templates/layout.html b/swh/web/templates/layout.html
--- a/swh/web/templates/layout.html
+++ b/swh/web/templates/layout.html
@@ -227,6 +227,9 @@
     <div class="content-wrapper">
       <section class="content">
         <div class="container" id="swh-web-content">
+          {% if swh_web_staging %}
+            <div class="swh-corner-ribbon">Staging</div>
+          {% endif %}
           {% block content %}{% endblock %}
         </div>
       </section>
diff --git a/swh/web/tests/test_templates.py b/swh/web/tests/test_templates.py
new file mode 100644
--- /dev/null
+++ b/swh/web/tests/test_templates.py
@@ -0,0 +1,25 @@
+# Copyright (C) 2021  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU Affero General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+import random
+
+from swh.web.common.utils import reverse
+from swh.web.config import STAGING_SERVER_NAMES
+from swh.web.tests.django_asserts import assert_contains, assert_not_contains
+from swh.web.tests.utils import check_http_get_response
+
+
+def test_layout_without_staging_ribbon(client):
+    url = reverse("swh-web-homepage")
+    resp = check_http_get_response(client, url, status_code=200)
+    assert_not_contains(resp, "swh-corner-ribbon")
+
+
+def test_layout_with_staging_ribbon(client):
+    url = reverse("swh-web-homepage")
+    resp = check_http_get_response(
+        client, url, status_code=200, server_name=random.choice(STAGING_SERVER_NAMES),
+    )
+    assert_contains(resp, "swh-corner-ribbon")