diff --git a/swh/model/hypothesis_strategies.py b/swh/model/hypothesis_strategies.py
--- a/swh/model/hypothesis_strategies.py
+++ b/swh/model/hypothesis_strategies.py
@@ -79,7 +79,7 @@
     return builds(
         OriginVisit,
         visit=integers(0, 1000),
-        origin=origins(),
+        origin=urls(),
         status=sampled_from(['ongoing', 'full', 'partial']),
         type=pgsql_text())
 
diff --git a/swh/model/model.py b/swh/model/model.py
--- a/swh/model/model.py
+++ b/swh/model/model.py
@@ -121,7 +121,7 @@
 class OriginVisit(BaseModel):
     """Represents a visit of an origin at a given point in time, by a
     SWH loader."""
-    origin = attr.ib(type=Origin)
+    origin = attr.ib(type=str)
     date = attr.ib(type=datetime.datetime)
     status = attr.ib(
         type=str,
@@ -149,7 +149,6 @@
         d = d.copy()
         date = d.pop('date')
         return cls(
-            origin=Origin.from_dict(d.pop('origin')),
             date=(date
                   if isinstance(date, datetime.datetime)
                   else dateutil.parser.parse(date)),
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
@@ -3,7 +3,6 @@
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
-import attr
 import copy
 
 from hypothesis import given
@@ -44,10 +43,7 @@
 def test_todict_origin_visits(origin_visit):
     obj = origin_visit.to_dict()
 
-    assert 'type' not in obj['origin']
-    origin2 = attr.evolve(origin_visit.origin, type=None)
-    origin_visit2 = attr.evolve(origin_visit, origin=origin2)
-    assert origin_visit2 == type(origin_visit).from_dict(obj)
+    assert origin_visit == type(origin_visit).from_dict(obj)
 
 
 def test_content_get_hash():