diff --git a/swh/web/api/views/snapshot.py b/swh/web/api/views/snapshot.py
--- a/swh/web/api/views/snapshot.py
+++ b/swh/web/api/views/snapshot.py
@@ -68,6 +68,20 @@
             :swh_web_api:`snapshot/6a3a2cf0b2b90ce7ae1cf0a221ed68035b686f5a/`
     """
 
+    def _resolve_alias(snapshot, branch):
+        while branch and branch['target_type'] == 'alias':
+            if branch['target'] in snapshot['branches']:
+                branch = snapshot['branches'][branch['target']]
+            else:
+                snp = service.lookup_snapshot(
+                    snapshot['id'], branches_from=branch['target'],
+                    branches_count=1)
+                if snp and branch['target'] in snp['branches']:
+                    branch = snp['branches'][branch['target']]
+                else:
+                    branch = None
+        return branch
+
     def _enrich_snapshot(snapshot):
         s = snapshot.copy()
         if 'branches' in s:
@@ -77,19 +91,10 @@
             }
             for k, v in s['branches'].items():
                 if v and v['target_type'] == 'alias':
-                    if v['target'] in s['branches']:
-                        branch_alias = s['branches'][v['target']]
-                        if branch_alias:
-                            v['target_url'] = branch_alias['target_url']
-                    else:
-                        snp = \
-                            service.lookup_snapshot(s['id'],
-                                                    branches_from=v['target'],
-                                                    branches_count=1)
-                        if snp and v['target'] in snp['branches']:
-                            branch = snp['branches'][v['target']]
-                            branch = utils.enrich_object(branch)
-                            v['target_url'] = branch['target_url']
+                    branch = _resolve_alias(snapshot, v)
+                    if branch:
+                        branch = utils.enrich_object(branch)
+                        v['target_url'] = branch['target_url']
         return s
 
     snapshot_content_max_size = get_config()['snapshot_content_max_size']