diff --git a/swh/web/common/converters.py b/swh/web/common/converters.py
--- a/swh/web/common/converters.py
+++ b/swh/web/common/converters.py
@@ -9,6 +9,8 @@
 
 from swh.core.utils import decode_with_escape
 from swh.model import hashutil
+from swh.storage.interface import PartialBranches
+
 from swh.web.common.typing import OriginInfo, OriginVisitInfo
 
 
@@ -352,7 +354,7 @@
 
 
 def from_snapshot(snapshot):
-    """Convert swh snapshot to serializable snapshot dictionary.
+    """Convert swh snapshot to serializable (partial) snapshot dictionary.
 
     """
     sv = from_swh(snapshot, hashess={"id", "target"}, bytess={"next_branch"})
@@ -369,6 +371,22 @@
     return sv
 
 
+def from_partial_branches(branches: PartialBranches):
+    """Convert PartialBranches to serializable partial snapshot dictionary
+
+    """
+    return from_snapshot(
+        {
+            "id": branches["id"],
+            "branches": {
+                branch_name: branch.to_dict() if branch else None
+                for (branch_name, branch) in branches["branches"].items()
+            },
+            "next_branch": branches["next_branch"],
+        }
+    )
+
+
 def from_directory_entry(dir_entry):
     """Convert swh directory to serializable directory dictionary.
 
diff --git a/swh/web/common/service.py b/swh/web/common/service.py
--- a/swh/web/common/service.py
+++ b/swh/web/common/service.py
@@ -1046,12 +1046,12 @@
         A dict filled with the snapshot content.
     """
     snapshot_id_bin = _to_sha1_bin(snapshot_id)
-    snapshot = storage.snapshot_get_branches(
+    partial_branches = storage.snapshot_get_branches(
         snapshot_id_bin, branches_from.encode(), branches_count, target_types
     )
-    if not snapshot:
-        raise NotFoundExc("Snapshot with id %s not found!" % snapshot_id)
-    return converters.from_snapshot(snapshot)
+    if not partial_branches:
+        raise NotFoundExc(f"Snapshot with id {snapshot_id} not found!")
+    return converters.from_partial_branches(partial_branches)
 
 
 def lookup_latest_origin_snapshot(
diff --git a/swh/web/tests/conftest.py b/swh/web/tests/conftest.py
--- a/swh/web/tests/conftest.py
+++ b/swh/web/tests/conftest.py
@@ -292,13 +292,13 @@
     def snapshot_get_branches(
         self, snapshot_id, branches_from="", branches_count=1000, target_types=None
     ):
-        snp = self.storage.snapshot_get_branches(
+        partial_branches = self.storage.snapshot_get_branches(
             hash_to_bytes(snapshot_id),
             branches_from.encode(),
             branches_count,
             target_types,
         )
-        return converters.from_snapshot(snp)
+        return converters.from_partial_branches(partial_branches)
 
     def snapshot_get_head(self, snapshot):
         if snapshot["branches"]["HEAD"]["target_type"] == "alias":