diff --git a/swh/web/client/__init__.py b/swh/web/client/__init__.py
--- a/swh/web/client/__init__.py
+++ b/swh/web/client/__init__.py
@@ -1 +1 @@
-from .client import WebAPIClient  # NoQA: F401
+from .client import WebAPIClient, typify  # NoQA: F401
diff --git a/swh/web/client/client.py b/swh/web/client/client.py
--- a/swh/web/client/client.py
+++ b/swh/web/client/client.py
@@ -67,7 +67,10 @@
     def to_pid(object_type, s):
         return PID(object_type=object_type, object_id=s)
 
-    def to_date(s):
+    # The date attribute is optional for Revision and Release object
+    def to_date(s: Optional[str], optional: Optional[bool] = False) -> datetime:
+        if optional and s is None:
+            return None
         return dateutil.parser.parse(s)
 
     def obj_type_of_entry_type(s):
@@ -89,12 +92,12 @@
         data["id"] = to_pid(obj_type, data["id"])
         data["directory"] = to_pid(DIRECTORY, data["directory"])
         for key in ("date", "committer_date"):
-            data[key] = to_date(data[key])
+            data[key] = to_date(data[key], optional=True)
         for parent in data["parents"]:
             parent["id"] = to_pid(REVISION, parent["id"])
     elif obj_type == RELEASE:
         data["id"] = to_pid(obj_type, data["id"])
-        data["date"] = to_date(data["date"])
+        data["date"] = to_date(data["date"], optional=True)
         data["target"] = to_pid(data["target_type"], data["target"])
     elif obj_type == DIRECTORY:
         dir_pid = None
diff --git a/swh/web/client/tests/test_web_api_client.py b/swh/web/client/tests/test_web_api_client.py
--- a/swh/web/client/tests/test_web_api_client.py
+++ b/swh/web/client/tests/test_web_api_client.py
@@ -10,6 +10,9 @@
 
 import pytest
 
+from swh.model.identifiers import REVISION
+
+from swh.web.client import typify
 from swh.web.client.auth import AuthenticationError
 from swh.model.identifiers import parse_persistent_identifier as parse_pid
 
@@ -220,3 +223,17 @@
     assert visits[0]["snapshot"] is None
     snapshot_pid = 'swh:1:snp:456550ea74af4e2eecaa406629efaaf0b9b5f976'
     assert visits[7]["snapshot"] == parse_pid(snapshot_pid)
+
+
+def test_typify_minimal_revision():
+    revision_data = {
+        'id': 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa',
+        'directory': 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa',
+        'date': None,
+        'committer_date': None,
+        'parents': []
+    }
+    revision_typed = typify(revision_data, REVISION)
+    pid = "swh:1:rev:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    assert revision_typed['id'] == parse_pid(pid)
+    assert revision_typed['date'] is None