From a62d7ac87a4ea6d881448945106ffff0959a2958 Mon Sep 17 00:00:00 2001
From: Joshua Valluru <326636767+joshua-berri@users.noreply.github.com>
Date: Tue, 3 Nov 2026 08:44:52 -0800
Subject: [PATCH] fix(accounting): preserve dates in serialized payloads

---
 litellm/accounting/snapshot.py           | 7 ++++++-
 tests/unit/accounting/test_projection.py | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/litellm/accounting/snapshot.py b/litellm/accounting/snapshot.py
index df22742b9f0..3464bb07d5a 100644
--- a/litellm/accounting/snapshot.py
+++ b/litellm/accounting/snapshot.py
@@ -1,4 +1,5 @@
 from collections.abc import Callable, Mapping, Sequence
+from datetime import datetime
 from typing import TYPE_CHECKING, Final
 
 from pydantic import TypeAdapter
@@ -112,6 +113,10 @@ def build_accounting_payload(
         )
     )
     return {
-        **{key: value for key, value in payload.items() if key in _ACCOUNTING_FIELDS},
+        **{
+            key: value.isoformat() if isinstance(value, datetime) else value
+            for key, value in payload.items()
+            if key in _ACCOUNTING_FIELDS
+        },
         "metadata": {key: value for key, value in metadata.items() if key in ACCOUNTING_METADATA_FIELDS},
     }
diff --git a/tests/unit/accounting/test_projection.py b/tests/unit/accounting/test_projection.py
index 90f830fac8b..8674d769c54 100644
--- a/tests/unit/accounting/test_projection.py
+++ b/tests/unit/accounting/test_projection.py
@@ -69,6 +69,7 @@ async def test_daily_projection_matches_legacy_writer(status: str, origin: str |
     restored: Final = _FIELDS.validate_json(json.dumps(accounting, default=str))
     stored_daily: Final = next(item for item in project(restored) if item.table == "LiteLLM_DailyUserSpend")
     assert dict(stored_daily.increments) == {name: legacy[name] for name, _ in stored_daily.increments}
+    assert stored_daily.key == projected.key
     assert not {"messages", "response", "proxy_server_request", "requester_ip_address"}.intersection(accounting)