diff --git a/swh/model/model.py b/swh/model/model.py
--- a/swh/model/model.py
+++ b/swh/model/model.py
@@ -97,6 +97,11 @@
     url = attr.ib(type=str)
     type = attr.ib(type=Optional[str], default=None)
 
+    def to_dict(self):
+        r = super().to_dict()
+        r.pop('type', None)
+        return r
+
 
 @attr.s
 class OriginVisit(BaseModel):
diff --git a/swh/model/tests/test_model.py b/swh/model/tests/test_model.py
--- a/swh/model/tests/test_model.py
+++ b/swh/model/tests/test_model.py
@@ -8,12 +8,16 @@
 from hypothesis import given
 
 from swh.model.model import Content
-from swh.model.hypothesis_strategies import objects
+from swh.model.hypothesis_strategies import objects, origins
 
 
 @given(objects())
 def test_todict_inverse_fromdict(objtype_and_obj):
     (obj_type, obj) = objtype_and_obj
+
+    if obj_type == 'origin':
+        return
+
     obj_as_dict = obj.to_dict()
     obj_as_dict_copy = copy.deepcopy(obj_as_dict)
 
@@ -27,6 +31,14 @@
     assert obj_as_dict == type(obj).from_dict(obj_as_dict).to_dict()
 
 
+@given(origins())
+def test_todict_origins(origin):
+    obj = origin.to_dict()
+
+    assert 'type' not in obj
+    assert type(origin)(url=origin.url) == type(origin).from_dict(obj)
+
+
 def test_content_get_hash():
     hashes = dict(
         sha1=b'foo', sha1_git=b'bar', sha256=b'baz', blake2s256=b'qux')