diff --git a/swh/indexer/cli.py b/swh/indexer/cli.py
--- a/swh/indexer/cli.py
+++ b/swh/indexer/cli.py
@@ -145,16 +145,16 @@
 
 
 def list_origins_by_producer(idx_storage, mappings, tool_ids):
-    start = ''
+    last = ''
     limit = 10000
     while True:
         origins = list(
             idx_storage.origin_intrinsic_metadata_search_by_producer(
-                start=start, limit=limit, ids_only=True,
+                last=last, limit=limit, ids_only=True,
                 mappings=mappings or None, tool_ids=tool_ids or None))
         if not origins:
             break
-        start = origins[-1] + '\x00'  # first possible string after this
+        last = origins[-1]
         yield from origins
 
 
diff --git a/swh/indexer/storage/__init__.py b/swh/indexer/storage/__init__.py
--- a/swh/indexer/storage/__init__.py
+++ b/swh/indexer/storage/__init__.py
@@ -783,14 +783,14 @@
     @remote_api_endpoint('origin_intrinsic_metadata/search/by_producer')
     @db_transaction_generator()
     def origin_intrinsic_metadata_search_by_producer(
-            self, start='', end=None, limit=100, ids_only=False,
+            self, last='', limit=100, ids_only=False,
             mappings=None, tool_ids=None,
             db=None, cur=None):
         """Returns the list of origins whose metadata contain all the terms.
 
         Args:
-            start (str): The minimum origin url to return
-            end (str): The maximum origin url to return
+            last (str): The last origin url returned by previous (paginated)
+                call.
             limit (int): The maximum number of results to return
             ids_only (bool): Determines whether only origin urls are
                 returned or the content as well
@@ -810,8 +810,9 @@
                   these metadata
 
         """
+        assert isinstance(last, str)
         res = db.origin_intrinsic_metadata_search_by_producer(
-            start, end, limit, ids_only, mappings, tool_ids, cur)
+            last, limit, ids_only, mappings, tool_ids, cur)
         if ids_only:
             for (origin,) in res:
                 yield origin
diff --git a/swh/indexer/storage/db.py b/swh/indexer/storage/db.py
--- a/swh/indexer/storage/db.py
+++ b/swh/indexer/storage/db.py
@@ -393,7 +393,7 @@
         yield from cur
 
     def origin_intrinsic_metadata_search_by_producer(
-            self, start, end, limit, ids_only, mappings, tool_ids, cur):
+            self, last, limit, ids_only, mappings, tool_ids, cur):
         if ids_only:
             keys = 'oim.id'
         else:
@@ -408,12 +408,9 @@
         args = []
 
         where = []
-        if start:
-            where.append('oim.id >= %s')
-            args.append(start)
-        if end:
-            where.append('oim.id <= %s')
-            args.append(end)
+        if last:
+            where.append('oim.id > %s')
+            args.append(last)
         if mappings is not None:
             where.append('oim.mappings && %s')
             args.append(mappings)
diff --git a/swh/indexer/storage/in_memory.py b/swh/indexer/storage/in_memory.py
--- a/swh/indexer/storage/in_memory.py
+++ b/swh/indexer/storage/in_memory.py
@@ -706,14 +706,14 @@
             yield result
 
     def origin_intrinsic_metadata_search_by_producer(
-            self, start='', end=None, limit=100, ids_only=False,
+            self, last='', limit=100, ids_only=False,
             mappings=None, tool_ids=None,
             db=None, cur=None):
         """Returns the list of origins whose metadata contain all the terms.
 
         Args:
-            start (str): The minimum origin url to return
-            end (str): The maximum origin url to return
+            last (str): The last origin url returned by previous (paginated)
+                call.
             limit (int): The maximum number of results to return
             ids_only (bool): Determines whether only origin ids are returned
                 or the content as well
@@ -733,13 +733,14 @@
                   these metadata
 
         """
+        assert isinstance(last, str)
         nb_results = 0
         if mappings is not None:
             mappings = frozenset(mappings)
         if tool_ids is not None:
             tool_ids = frozenset(tool_ids)
         for entry in self._origin_intrinsic_metadata.get_all():
-            if entry['id'] < start or (end and entry['id'] > end):
+            if entry['id'] <= last:
                 continue
             if nb_results >= limit:
                 return
diff --git a/swh/indexer/tests/storage/test_storage.py b/swh/indexer/tests/storage/test_storage.py
--- a/swh/indexer/tests/storage/test_storage.py
+++ b/swh/indexer/tests/storage/test_storage.py
@@ -1553,22 +1553,29 @@
         endpoint = self.storage.origin_intrinsic_metadata_search_by_producer
 
         # test pagination
+        # no 'last' param, return all origins
         self.assertCountEqual(
             endpoint(ids_only=True),
             [self.origin_url_1, self.origin_url_2, self.origin_url_3])
+        # 'last' is < than origin_1, return everything
         self.assertCountEqual(
-            endpoint(start=self.origin_url_1, ids_only=True),
+            endpoint(last=self.origin_url_1[:-1], ids_only=True),
             [self.origin_url_1, self.origin_url_2, self.origin_url_3])
+        # 'last' is origin_3, return nothing
         self.assertCountEqual(
-            endpoint(start=self.origin_url_1, limit=2, ids_only=True),
+            endpoint(last=self.origin_url_3, ids_only=True),
+            [])
+
+        # test limit argument
+        self.assertCountEqual(
+            endpoint(last=self.origin_url_1[:-1], limit=2, ids_only=True),
             [self.origin_url_1, self.origin_url_2])
         self.assertCountEqual(
-            endpoint(start=self.origin_url_1+'2', ids_only=True),
+            endpoint(last=self.origin_url_1, limit=2, ids_only=True),
             [self.origin_url_2, self.origin_url_3])
         self.assertCountEqual(
-            endpoint(start=self.origin_url_1+'2', end=self.origin_url_3[:-1],
-                     ids_only=True),
-            [self.origin_url_2])
+            endpoint(last=self.origin_url_2, limit=2, ids_only=True),
+            [self.origin_url_3])
 
         # test mappings filtering
         self.assertCountEqual(