diff --git a/src/wikiq/__init__.py b/src/wikiq/__init__.py
index 6172fa4..33dcca8 100755
--- a/src/wikiq/__init__.py
+++ b/src/wikiq/__init__.py
@@ -587,8 +587,8 @@ class WikiqParser:
             else:
                 self.output_file = open(output_file, "wb")
 
-        # Checkpoint file for tracking resume point
-        self.checkpoint_file = None
+        # Checkpoint for tracking resume point (path only, no open file handle for NFS safety)
+        self.checkpoint_path = None
         self.checkpoint_state = {}  # namespace -> (pageid, revid) or None -> (pageid, revid)
 
     def request_shutdown(self):
@@ -624,39 +624,40 @@ class WikiqParser:
         return path.parent / f"{path.stem}.part{part_num}{path.suffix}"
 
     def _open_checkpoint(self, output_file):
-        """Open checkpoint file for writing. Keeps file open for performance."""
+        """Enable checkpointing for the given output file."""
         if (not self.output_jsonl and not self.output_parquet) or output_file == sys.stdout.buffer:
             return
-        checkpoint_path = get_checkpoint_path(output_file, self.partition_namespaces)
-        Path(checkpoint_path).parent.mkdir(parents=True, exist_ok=True)
-        self.checkpoint_file = open(checkpoint_path, 'w')
-        print(f"Checkpoint file opened: {checkpoint_path}", file=sys.stderr)
+        self.checkpoint_path = get_checkpoint_path(output_file, self.partition_namespaces)
+        Path(self.checkpoint_path).parent.mkdir(parents=True, exist_ok=True)
+        print(f"Checkpoint enabled: {self.checkpoint_path}", file=sys.stderr)
 
     def _update_checkpoint(self, pageid, revid, namespace=None, part=0):
-        """Update checkpoint state and write to file."""
-        if self.checkpoint_file is None:
+        """Update checkpoint state and write atomically (NFS-safe)."""
+        if self.checkpoint_path is None:
             return
         if self.partition_namespaces:
             self.checkpoint_state[namespace] = {"pageid": pageid, "revid": revid, "part": part}
         else:
             self.checkpoint_state = {"pageid": pageid, "revid": revid, "part": part}
-        self.checkpoint_file.seek(0)
-        self.checkpoint_file.truncate()
-        json.dump(self.checkpoint_state, self.checkpoint_file)
-        self.checkpoint_file.flush()
+        # Atomic write: write to temp file, then rename
+        temp_path = self.checkpoint_path + ".tmp"
+        with open(temp_path, 'w') as f:
+            json.dump(self.checkpoint_state, f)
+        os.replace(temp_path, self.checkpoint_path)
 
     def _close_checkpoint(self, delete=False):
-        """Close checkpoint file, optionally deleting it."""
-        if self.checkpoint_file is None:
+        """Clean up checkpoint, optionally deleting it."""
+        if self.checkpoint_path is None:
             return
-        checkpoint_path = self.checkpoint_file.name
-        self.checkpoint_file.close()
-        self.checkpoint_file = None
-        if delete and os.path.exists(checkpoint_path):
-            os.remove(checkpoint_path)
-            print(f"Checkpoint file deleted (processing complete): {checkpoint_path}", file=sys.stderr)
-        else:
-            print(f"Checkpoint file preserved for resume: {checkpoint_path}", file=sys.stderr)
+        if delete and os.path.exists(self.checkpoint_path):
+            os.remove(self.checkpoint_path)
+            print(f"Checkpoint deleted: {self.checkpoint_path}", file=sys.stderr)
+        elif os.path.exists(self.checkpoint_path):
+            print(f"Checkpoint preserved for resume: {self.checkpoint_path}", file=sys.stderr)
+        # Clean up any leftover temp file
+        temp_path = self.checkpoint_path + ".tmp"
+        if os.path.exists(temp_path):
+            os.remove(temp_path)
 
     def _write_batch(self, row_buffer, schema, writer, pq_writers, ns_base_paths, sorting_cols, namespace=None, part_numbers=None):
         """Write a batch of rows to the appropriate writer.