diff --git a/chatmaild/src/chatmaild/filedict.py b/chatmaild/src/chatmaild/filedict.py
index 4515867..3d9caf8 100644
--- a/chatmaild/src/chatmaild/filedict.py
+++ b/chatmaild/src/chatmaild/filedict.py
@@ -1,6 +1,6 @@
 import os
 import logging
-import marshal
+import json
 import filelock
 from contextlib import contextmanager
 
@@ -20,14 +20,14 @@ class FileDict:
             data = self.read()
             yield data
             write_path = self.path.with_suffix(".tmp")
-            with write_path.open("wb") as f:
-                marshal.dump(data, f)
+            with write_path.open("w") as f:
+                json.dump(data, f)
             os.rename(write_path, self.path)
 
     def read(self):
         try:
-            with self.path.open("rb") as f:
-                return marshal.load(f)
+            with self.path.open("r") as f:
+                return json.load(f)
         except FileNotFoundError:
             return {}
         except Exception:
diff --git a/chatmaild/src/chatmaild/metadata.py b/chatmaild/src/chatmaild/metadata.py
index 8900e2c..fb5628f 100644
--- a/chatmaild/src/chatmaild/metadata.py
+++ b/chatmaild/src/chatmaild/metadata.py
@@ -35,7 +35,7 @@ class Notifier:
         self.to_notify_queue = Queue()
 
     def get_metadata_dict(self, addr):
-        return FileDict(self.vmail_dir / addr / "metadata.marshalled")
+        return FileDict(self.vmail_dir / addr / "metadata.json")
 
     def add_token(self, addr, token):
         with self.get_metadata_dict(addr).modify() as data: