diff --git a/litellm/llms/chatgpt/db_authenticator.py b/litellm/llms/chatgpt/db_authenticator.py
index 46f6630bb7c..e7098878cc5 100644
--- a/litellm/llms/chatgpt/db_authenticator.py
+++ b/litellm/llms/chatgpt/db_authenticator.py
@@ -176,6 +176,7 @@ async def persist_credential_to_db(item: CredentialItem) -> None:
     # would bind the stale None reference rather than the live client.
     from litellm.proxy.common_utils.encrypt_decrypt_utils import encrypt_value_helper
     from litellm.proxy.proxy_server import prisma_client
+    from litellm.proxy.utils import jsonify_object
 
     if prisma_client is None:
         verbose_logger.debug(
@@ -191,19 +192,25 @@ async def persist_credential_to_db(item: CredentialItem) -> None:
         "type": CREDENTIAL_TYPE,
         "custom_llm_provider": "chatgpt",
     }
+    # Prisma's Json columns want JSON-serialized strings, not raw dicts —
+    # see credential_endpoints/endpoints.py for the canonical pattern.
+    jsonified = jsonify_object(
+        {
+            "credential_values": encrypted_values,
+            "credential_info": credential_info,
+        }
+    )
     await prisma_client.db.litellm_credentialstable.upsert(
         where={"credential_name": item.credential_name},
         data={
             "create": {
                 "credential_name": item.credential_name,
-                "credential_values": encrypted_values,
-                "credential_info": credential_info,
+                **jsonified,
                 "created_by": "chatgpt_oauth_flow",
                 "updated_by": "chatgpt_oauth_flow",
             },
             "update": {
-                "credential_values": encrypted_values,
-                "credential_info": credential_info,
+                **jsonified,
                 "updated_by": "chatgpt_oauth_flow",
             },
         },
diff --git a/litellm/llms/github_copilot/db_authenticator.py b/litellm/llms/github_copilot/db_authenticator.py
index 4d1ddf5e703..8ba126b896f 100644
--- a/litellm/llms/github_copilot/db_authenticator.py
+++ b/litellm/llms/github_copilot/db_authenticator.py
@@ -180,6 +180,7 @@ async def persist_credential_to_db(item: CredentialItem) -> None:
     # would bind the stale None reference rather than the live client.
     from litellm.proxy.common_utils.encrypt_decrypt_utils import encrypt_value_helper
     from litellm.proxy.proxy_server import prisma_client
+    from litellm.proxy.utils import jsonify_object
 
     if prisma_client is None:
         verbose_logger.debug(
@@ -195,19 +196,24 @@ async def persist_credential_to_db(item: CredentialItem) -> None:
         "type": CREDENTIAL_TYPE,
         "custom_llm_provider": "github_copilot",
     }
+    # Prisma's Json columns want JSON-serialized strings, not raw dicts.
+    jsonified = jsonify_object(
+        {
+            "credential_values": encrypted_values,
+            "credential_info": credential_info,
+        }
+    )
     await prisma_client.db.litellm_credentialstable.upsert(
         where={"credential_name": item.credential_name},
         data={
             "create": {
                 "credential_name": item.credential_name,
-                "credential_values": encrypted_values,
-                "credential_info": credential_info,
+                **jsonified,
                 "created_by": "copilot_oauth_flow",
                 "updated_by": "copilot_oauth_flow",
             },
             "update": {
-                "credential_values": encrypted_values,
-                "credential_info": credential_info,
+                **jsonified,
                 "updated_by": "copilot_oauth_flow",
             },
         },
diff --git a/tests/test_litellm/llms/chatgpt/test_chatgpt_db_authenticator.py b/tests/test_litellm/llms/chatgpt/test_chatgpt_db_authenticator.py
index aa950abd68d..5d620e1844e 100644
--- a/tests/test_litellm/llms/chatgpt/test_chatgpt_db_authenticator.py
+++ b/tests/test_litellm/llms/chatgpt/test_chatgpt_db_authenticator.py
@@ -1,3 +1,4 @@
+import json
 from unittest.mock import MagicMock, patch
 
 import pytest
@@ -178,11 +179,12 @@ class TestPersistCredentialToDb:
         assert kwargs["where"] == {"credential_name": "test"}
         create = kwargs["data"]["create"]
         assert create["credential_name"] == "test"
-        assert create["credential_values"] == {
+        # Prisma Json columns receive pre-serialized JSON strings.
+        assert json.loads(create["credential_values"]) == {
             "access_token": "enc(a)",
             "refresh_token": "enc(r)",
         }
-        assert create["credential_info"] == {"type": CREDENTIAL_TYPE}
+        assert json.loads(create["credential_info"]) == {"type": CREDENTIAL_TYPE}
         update = kwargs["data"]["update"]
         assert update["credential_values"] == create["credential_values"]
 
diff --git a/tests/test_litellm/llms/github_copilot/test_copilot_db_authenticator.py b/tests/test_litellm/llms/github_copilot/test_copilot_db_authenticator.py
index 95877f8d782..ba0a676b679 100644
--- a/tests/test_litellm/llms/github_copilot/test_copilot_db_authenticator.py
+++ b/tests/test_litellm/llms/github_copilot/test_copilot_db_authenticator.py
@@ -1,3 +1,4 @@
+import json
 from unittest.mock import MagicMock, patch
 
 import pytest
@@ -225,10 +226,14 @@ class TestPersistCredentialToDb:
         fake_prisma.db.litellm_credentialstable.upsert.assert_called_once()
         kwargs = fake_prisma.db.litellm_credentialstable.upsert.call_args.kwargs
         assert kwargs["where"] == {"credential_name": "c"}
-        assert kwargs["data"]["create"]["credential_values"] == {
+        # Prisma Json columns receive pre-serialized JSON strings.
+        assert json.loads(kwargs["data"]["create"]["credential_values"]) == {
             "access_token": "enc(gho_abc)"
         }
-        assert kwargs["data"]["create"]["credential_info"]["type"] == CREDENTIAL_TYPE
+        assert (
+            json.loads(kwargs["data"]["create"]["credential_info"])["type"]
+            == CREDENTIAL_TYPE
+        )
 
 
 class _Awaitable: