diff --git a/swh/deposit/api/collection.py b/swh/deposit/api/collection.py
--- a/swh/deposit/api/collection.py
+++ b/swh/deposit/api/collection.py
@@ -21,6 +21,7 @@
     ParsedRequestHeaders,
     Receipt,
     get_collection_by_name,
+    guess_deposit_origin_url,
 )
 
 
@@ -132,9 +133,11 @@
                 # then no parent for that deposit, deposit_parent already None
                 pass
 
-        return Deposit(
+        deposit = Deposit(
             collection=collection,
             external_id=external_id or "",
             client=client,
             parent=deposit_parent,
         )
+        deposit.origin_url = guess_deposit_origin_url(deposit)
+        return deposit
diff --git a/swh/deposit/api/common.py b/swh/deposit/api/common.py
--- a/swh/deposit/api/common.py
+++ b/swh/deposit/api/common.py
@@ -137,6 +137,11 @@
     return collection
 
 
+def guess_deposit_origin_url(deposit: Deposit):
+    """Guesses an origin url for the given deposit."""
+    return "%s/%s" % (deposit.client.provider_url.rstrip("/"), deposit.external_id,)
+
+
 class AuthenticatedAPIView(APIView):
     """Mixin intended as a based API view to enforce the basic
        authentication check
diff --git a/swh/deposit/migrations/0021_deposit_origin_url_20201124_1438.py b/swh/deposit/migrations/0021_deposit_origin_url_20201124_1438.py
new file mode 100644
--- /dev/null
+++ b/swh/deposit/migrations/0021_deposit_origin_url_20201124_1438.py
@@ -0,0 +1,28 @@
+from django.db import migrations, models
+
+from swh.deposit.api.common import guess_deposit_origin_url
+from swh.deposit.models import Deposit
+
+
+def fill_origin_url(apps, schema_editor):
+    for deposit in Deposit.objects.all():
+        if deposit.origin_url is None:
+            deposit.origin_url = guess_deposit_origin_url()
+            deposit.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("deposit", "0020_auto_20200929_0855"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="deposit", name="origin_url", field=models.TextField(null=True),
+        ),
+        migrations.RunPython(fill_origin_url),
+        migrations.AlterField(
+            model_name="deposit", name="external_id", field=models.TextField(null=True),
+        ),
+    ]
diff --git a/swh/deposit/models.py b/swh/deposit/models.py
--- a/swh/deposit/models.py
+++ b/swh/deposit/models.py
@@ -121,8 +121,10 @@
     complete_date = models.DateTimeField(null=True)
     # collection concerned by the deposit
     collection = models.ForeignKey("DepositCollection", models.DO_NOTHING)
-    # Deposit's external identifier
+    # Deprecated: Deposit's external identifier
     external_id = models.TextField()
+    # URL of the origin of this deposit, null if this is a metadata-only deposit
+    origin_url = models.TextField(null=True)
     # Deposit client
     client = models.ForeignKey("DepositClient", models.DO_NOTHING)
     # SWH's loading result identifier
@@ -149,6 +151,7 @@
             "reception_date": self.reception_date,
             "collection": self.collection.name,
             "external_id": self.external_id,
+            "origin_url": self.origin_url,
             "client": self.client.username,
             "status": self.status,
         }
@@ -157,10 +160,6 @@
             d["status_detail"] = self.status_detail
         return str(d)
 
-    @property
-    def origin_url(self):
-        return "%s/%s" % (self.client.provider_url.rstrip("/"), self.external_id)
-
 
 def client_directory_path(instance: "DepositRequest", filename: str) -> str:
     """Callable to determine the upload archive path. This defaults to
diff --git a/swh/deposit/tests/api/test_deposit_private_read_metadata.py b/swh/deposit/tests/api/test_deposit_private_read_metadata.py
--- a/swh/deposit/tests/api/test_deposit_private_read_metadata.py
+++ b/swh/deposit/tests/api/test_deposit_private_read_metadata.py
@@ -44,6 +44,7 @@
     """
     deposit = partial_deposit
     deposit.external_id = "some-external-id"
+    deposit.origin_url = f"https://hal-test.archives-ouvertes.fr/{deposit.external_id}"
     deposit.save()
 
     metadata_xml_atoms = [
@@ -107,6 +108,7 @@
     """
     deposit = partial_deposit
     deposit.external_id = "some-external-id"
+    deposit.origin_url = f"https://hal-test.archives-ouvertes.fr/{deposit.external_id}"
     deposit.save()
     metadata_xml_atoms = [
         atom_dataset[atom_key] for atom_key in ["entry-data2", "entry-data3"]
@@ -179,6 +181,7 @@
     """
     deposit = partial_deposit
     deposit.external_id = "hal-01243065"
+    deposit.origin_url = f"https://hal-test.archives-ouvertes.fr/{deposit.external_id}"
     deposit.save()
 
     # add metadata to the deposit with datePublished and dateCreated