diff --git a/ardumont/nixguix/group_by_extension.py b/ardumont/nixguix/group_by_extension.py
new file mode 100644
index 0000000..61d3baf
--- /dev/null
+++ b/ardumont/nixguix/group_by_extension.py
@@ -0,0 +1,89 @@
+#!/usr/bin/env python3
+
+# Copyright (C) 2020 the Software Heritage developers
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+# Use sample
+# python3 -m group_by_extension --file-with-failures all-failures.json  | jq .
+# {
+#   ".tar.gz": 308,
+#   ".tar.xz": 152,
+#   ".tar.bz2": 79,
+#   ".tar.lz": 6,
+#   ".lisp": 1,
+#   ".tgz": 40,
+#   "no-extension": 106,
+#   ".1.0": 1,
+#   ".el?id=dcc9ba03252ee5d39e03bba31b420e0708c3ba0c": 1,
+#   ".11": 1,
+#   ".tar.z": 1,
+#   ".1.5": 1,
+#   ".4.2": 1,
+#   ".sf3": 1,
+#   ".zip": 23,
+#   ".7z": 1,
+#   ".install.gz": 1,
+#   ".gz": 1,
+#   ".tar.lzma": 1,
+#   ".14.6": 1,
+#   ".tar.gz?uuid=tklib-0-6": 1,
+#   ".tar.Z": 1,
+#   ".1": 1,
+#   ".py": 1,
+#   ".tbz": 79,
+#   ".8.3;sf=tgz": 1,
+#   ".git;a=snapshot;h=V7_3_0p3;sf=tgz": 1,
+#   ".0-tar.gz": 1,
+#   ".tar": 1
+# }
+
+import os
+import json
+
+from collections import defaultdict
+from typing import Dict, List
+
+import click
+
+known_single_extension = [
+    ".zip", ".tbz", ".tbz2", ".7z", ".tar", ".lisp", ".el", ".py", ".tgz",
+    ".sf3"
+]
+
+
+@click.command()
+@click.option('--file-with-failures',
+              help='JSON File with list of origins with failures')
+def main(file_with_failures):
+    with open(file_with_failures, 'r') as f:
+        data = json.loads(f.read())
+
+    url_per_extension: Dict[str, List[str]] = defaultdict(list)
+    for url in data:
+        prefix, ext = os.path.splitext(url)
+        if not ext:
+            url_per_extension["no-extension"].append(url)
+            continue
+
+        if ext in known_single_extension:  # known unique extension
+            url_per_extension[ext].append(url)
+            continue
+
+        prefix, ext2 = os.path.splitext(prefix)
+        if not ext2:  # unique extension
+            url_per_extension[ext].append(url)
+            continue
+
+        # etension is double e.g. .tar.gz, etc...
+        url_per_extension[f"{ext2}{ext}"].append(url)
+
+    summary: Dict[str, int] = {}
+    for ext, urls in url_per_extension.items():
+        summary[ext] = len(urls)
+
+    print(json.dumps(summary))
+
+
+if __name__ == '__main__':
+    main()