diff --git a/swh/web/api/views/origin.py b/swh/web/api/views/origin.py
--- a/swh/web/api/views/origin.py
+++ b/swh/web/api/views/origin.py
@@ -21,6 +21,7 @@
 from swh.web.common import archive
 from swh.web.common.exc import BadInputExc
 from swh.web.common.origin_visits import get_origin_visits
+from swh.web.common.typing import OriginInfo
 from swh.web.common.utils import origin_visit_types, reverse
 
 DOC_RETURN_ORIGIN = """
@@ -143,6 +144,7 @@
     return api_lookup(
         archive.lookup_origin,
         ori_dict,
+        lookup_similar_urls=False,
         notfound_msg=error_msg,
         enrich_fn=enrich_origin,
         request=request,
@@ -326,7 +328,7 @@
 
     """
     result = {}
-    origin_query = {"url": origin_url}
+    origin_query: OriginInfo = {"url": origin_url}
     notfound_msg = "No origin {} found".format(origin_url)
     url_args_next = {"origin_url": origin_url}
     per_page = int(request.query_params.get("per_page", "10"))
@@ -347,6 +349,9 @@
         for v in visits:
             yield v
 
+    # check origin existence in the archive
+    archive.lookup_origin(origin_query, lookup_similar_urls=False)
+
     results = api_lookup(
         _lookup_origin_visits,
         origin_query,
@@ -412,6 +417,9 @@
 
             :swh_web_api:`origin/https://github.com/hylang/hy/visit/latest/`
     """
+    # check origin existence in the archive
+    archive.lookup_origin({"url": origin_url}, lookup_similar_urls=False)
+
     require_snapshot = request.query_params.get("require_snapshot", "false")
     return api_lookup(
         archive.lookup_origin_visit_latest,
@@ -453,6 +461,9 @@
 
             :swh_web_api:`origin/https://github.com/hylang/hy/visit/1/`
     """
+    # check origin existence in the archive
+    archive.lookup_origin({"url": origin_url}, lookup_similar_urls=False)
+
     return api_lookup(
         archive.lookup_origin_visit,
         origin_url,
@@ -491,6 +502,9 @@
 
             :swh_web_api:`origin/https://github.com/python/cpython/intrinsic-metadata`
     """
+    # check origin existence in the archive
+    archive.lookup_origin({"url": origin_url}, lookup_similar_urls=False)
+
     return api_lookup(
         archive.lookup_origin_intrinsic_metadata,
         origin_url,
diff --git a/swh/web/common/archive.py b/swh/web/common/archive.py
--- a/swh/web/common/archive.py
+++ b/swh/web/common/archive.py
@@ -232,18 +232,20 @@
     return converters.from_swh(lic, hashess={"id"})
 
 
-def lookup_origin(origin: OriginInfo) -> OriginInfo:
+def lookup_origin(origin: OriginInfo, lookup_similar_urls: bool = True) -> OriginInfo:
     """Return information about the origin matching dict origin.
 
     Args:
         origin: origin's dict with 'url' key
+        lookup_similar_urls: if :const:`True`, lookup origin with and
+            without trailing slash in its URL
 
     Returns:
         origin information as dict.
 
     """
     origin_urls = [origin["url"]]
-    if origin["url"]:
+    if origin["url"] and lookup_similar_urls:
         # handle case when user provided an origin url with a trailing
         # slash while the url in storage does not have it (e.g. GitHub)
         if origin["url"].endswith("/"):
diff --git a/swh/web/tests/api/views/test_origin.py b/swh/web/tests/api/views/test_origin.py
--- a/swh/web/tests/api/views/test_origin.py
+++ b/swh/web/tests/api/views/test_origin.py
@@ -32,24 +32,26 @@
 from swh.web.tests.utils import check_api_get_responses
 
 
-def test_api_lookup_origin_visits_raise_error(api_client, mocker):
+def test_api_lookup_origin_visits_raise_error(api_client, origin, mocker):
     mock_get_origin_visits = mocker.patch("swh.web.api.views.origin.get_origin_visits")
     err_msg = "voluntary error to check the bad request middleware."
 
     mock_get_origin_visits.side_effect = BadInputExc(err_msg)
 
-    url = reverse("api-1-origin-visits", url_args={"origin_url": "http://foo"})
+    url = reverse("api-1-origin-visits", url_args={"origin_url": origin["url"]})
     rv = check_api_get_responses(api_client, url, status_code=400)
     assert rv.data == {"exception": "BadInputExc", "reason": err_msg}
 
 
-def test_api_lookup_origin_visits_raise_swh_storage_error_db(api_client, mocker):
+def test_api_lookup_origin_visits_raise_swh_storage_error_db(
+    api_client, origin, mocker
+):
     mock_get_origin_visits = mocker.patch("swh.web.api.views.origin.get_origin_visits")
     err_msg = "Storage exploded! Will be back online shortly!"
 
     mock_get_origin_visits.side_effect = StorageDBError(err_msg)
 
-    url = reverse("api-1-origin-visits", url_args={"origin_url": "http://foo"})
+    url = reverse("api-1-origin-visits", url_args={"origin_url": origin["url"]})
     rv = check_api_get_responses(api_client, url, status_code=503)
     assert rv.data == {
         "exception": "StorageDBError",
@@ -57,13 +59,15 @@
     }
 
 
-def test_api_lookup_origin_visits_raise_swh_storage_error_api(api_client, mocker):
+def test_api_lookup_origin_visits_raise_swh_storage_error_api(
+    api_client, origin, mocker
+):
     mock_get_origin_visits = mocker.patch("swh.web.api.views.origin.get_origin_visits")
     err_msg = "Storage API dropped dead! Will resurrect asap!"
 
     mock_get_origin_visits.side_effect = StorageAPIError(err_msg)
 
-    url = reverse("api-1-origin-visits", url_args={"origin_url": "http://foo"})
+    url = reverse("api-1-origin-visits", url_args={"origin_url": origin["url"]})
     rv = check_api_get_responses(api_client, url, status_code=503)
     assert rv.data == {
         "exception": "StorageAPIError",
@@ -837,3 +841,27 @@
         assert {o["url"] for o in rv.data} == {
             o["url"] for o in archived_origins if o["type"] == visit_type
         }
+
+
+@pytest.mark.parametrize(
+    "view_name, extra_args",
+    [
+        ("api-1-origin", {}),
+        ("api-1-origin-visits", {}),
+        ("api-1-origin-visit", {"visit_id": 1}),
+        ("api-1-origin-visit-latest", {}),
+        ("api-origin-intrinsic-metadata", {}),
+    ],
+)
+def test_api_origin_by_url_with_extra_trailing_slash(
+    api_client, origin, view_name, extra_args
+):
+    origin_url = origin["url"]
+    assert not origin_url.endswith("/")
+    origin_url = origin_url + "/"
+    url = reverse(view_name, url_args={"origin_url": origin_url, **extra_args})
+    rv = check_api_get_responses(api_client, url, status_code=404)
+    assert rv.data == {
+        "exception": "NotFoundExc",
+        "reason": f"Origin with url {origin_url} not found!",
+    }