diff --git a/swh/deposit/api/private/__init__.py b/swh/deposit/api/private/__init__.py
index f4acbba4..59369eba 100644
--- a/swh/deposit/api/private/__init__.py
+++ b/swh/deposit/api/private/__init__.py
@@ -1,51 +1,50 @@
 # Copyright (C) 2017-2018 The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
+from swh.deposit import utils
 
 from ...config import METADATA_TYPE
 from ...models import DepositRequest, Deposit
 
 
 class DepositReadMixin:
     """Deposit Read mixin
 
     """
 
     def _deposit_requests(self, deposit, request_type):
         """Given a deposit, yields its associated deposit_request
 
         Args:
             deposit (Deposit): Deposit to list requests for
             request_type (str): Archive or metadata type
 
         Yields:
             deposit requests of type request_type associated to the deposit
 
         """
         if isinstance(deposit, int):
             deposit = Deposit.objects.get(pk=deposit)
 
         deposit_requests = DepositRequest.objects.filter(
             type=self.deposit_request_types[request_type],
             deposit=deposit).order_by('id')
 
         for deposit_request in deposit_requests:
             yield deposit_request
 
     def _metadata_get(self, deposit):
         """Given a deposit, aggregate all metadata requests.
 
         Args:
             deposit (Deposit): The deposit instance to extract
             metadata from.
 
         Returns:
             metadata dict from the deposit.
 
         """
-        metadata = {}
-        for dr in self._deposit_requests(deposit, request_type=METADATA_TYPE):
-            metadata.update(dr.metadata)
-        return metadata
+        metadata = self._deposit_requests(deposit, request_type=METADATA_TYPE)
+        return utils.merge((m.metadata for m in metadata))
diff --git a/swh/deposit/tests/test_utils.py b/swh/deposit/tests/test_utils.py
new file mode 100644
index 00000000..9e02c619
--- /dev/null
+++ b/swh/deposit/tests/test_utils.py
@@ -0,0 +1,44 @@
+# Copyright (C) 2018  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+import unittest
+
+from nose.tools import istest
+
+from swh.deposit import utils
+
+
+class UtilsTestCase(unittest.TestCase):
+    """Utils library
+
+    """
+    @istest
+    def convert(self):
+        d0 = {
+            'author': 'someone',
+            'a': 1
+        }
+
+        d1 = {
+            'author': ['author0', 'author1'],
+            'b': {
+                '1': '2'
+            }
+        }
+
+        d2 = {
+            'author': 'else',
+        }
+
+        actual_merge = utils.merge([d0, d1, d2])
+
+        expected_merge = {
+            'a': 1,
+            'author': ['someone', 'author0', 'author1', 'else'],
+            'b': {
+                '1': '2'
+            }
+        }
+        self.assertEquals(actual_merge, expected_merge)
diff --git a/swh/deposit/utils.py b/swh/deposit/utils.py
new file mode 100644
index 00000000..04c9d3b3
--- /dev/null
+++ b/swh/deposit/utils.py
@@ -0,0 +1,15 @@
+# Copyright (C) 2018 The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+
+def merge(dicts):
+    """Given an iteratof of dicts, merge them losing no information.
+
+    """
+    d = {}
+    for data in dicts:
+        print(data)
+        d.update(data)
+    return d