diff --git a/litellm/proxy/_types.py b/litellm/proxy/_types.py
index abf61a909b2..228e80da4bd 100644
--- a/litellm/proxy/_types.py
+++ b/litellm/proxy/_types.py
@@ -1860,6 +1860,21 @@ class CustomerBase(LiteLLMPydanticObjectBase):
     blocked: bool = False
 
 
+def reject_unknown_customer_fields(request: type[BaseModel], values: object) -> object:
+    if not isinstance(values, dict):
+        return values
+    unknown: Final = tuple(sorted(str(key) for key in values if key not in request.model_fields))  # pyright: ignore[reportUnknownVariableType, reportUnknownArgumentType]  # raw request body
+    if not unknown:
+        return values
+    on_budget: Final = tuple(field for field in unknown if field in BudgetNewRequest.model_fields)
+    hint: Final = (
+        f" {', '.join(on_budget)}: these live on the customer's budget object, update it with /budget/update."
+        if on_budget
+        else ""
+    )
+    raise ValueError(f"Unknown fields: {', '.join(unknown)}.{hint}")
+
+
 class NewCustomerRequest(BudgetNewRequest):
     """
     Create a new customer, allocate a budget to them
@@ -1877,6 +1892,11 @@ class NewCustomerRequest(BudgetNewRequest):
     models: list[str] | None = None
     object_permission: LiteLLM_ObjectPermissionBase | None = None
 
+    @model_validator(mode="before")
+    @classmethod
+    def reject_unknown_fields(cls, values: object) -> object:
+        return reject_unknown_customer_fields(cls, values)
+
     @model_validator(mode="before")
     @classmethod
     def check_user_info(cls, values):
@@ -1904,6 +1924,11 @@ class UpdateCustomerRequest(LiteLLMPydanticObjectBase):
     models: list[str] | None = None
     object_permission: LiteLLM_ObjectPermissionBase | None = None
 
+    @model_validator(mode="before")
+    @classmethod
+    def reject_unknown_fields(cls, values: object) -> object:
+        return reject_unknown_customer_fields(cls, values)
+
 
 class DeleteCustomerRequest(LiteLLMPydanticObjectBase):
     """
diff --git a/litellm/proxy/management_endpoints/customer_endpoints.py b/litellm/proxy/management_endpoints/customer_endpoints.py
index aec5e6840a5..bd202b85f73 100644
--- a/litellm/proxy/management_endpoints/customer_endpoints.py
+++ b/litellm/proxy/management_endpoints/customer_endpoints.py
@@ -353,7 +353,6 @@ async def new_end_user(
     - allowed_model_region: Optional[Union[Literal["eu"], Literal["us"]]] - Require all user requests to use models in this specific region.
     - default_model: Optional[str] - If no equivalent model in the allowed region, default all requests to this model.
     - models: Optional[list[str]] - Restrict this customer's access to the listed models.
-    - metadata: Optional[dict] = Metadata for customer, store information for customer. Example metadata = {"data_training_opt_out": True}
     - budget_duration: Optional[str] - Budget is reset at the end of specified duration. If not set, budget is never reset. You can set duration as seconds ("30s"), minutes ("30m"), hours ("30h"), days ("30d").
     - tpm_limit: Optional[int] - [Not Implemented Yet] Specify tpm limit for a given customer (Tokens per minute)
     - rpm_limit: Optional[int] - [Not Implemented Yet] Specify rpm limit for a given customer (Requests per minute)
@@ -387,7 +386,7 @@ async def new_end_user(
         --header 'Content-Type: application/json' \
         --data '{
             "user_id" : "ishaan-jaff-3",
-            "allowed_region": "eu",
+            "allowed_model_region": "eu",
             "budget_id": "free_tier",
             "models": ["gpt-4o-mini"],
             "default_model": "azure/gpt-3.5-turbo-eu"
diff --git a/tests/integration/management/test_customer_unknown_fields.py b/tests/integration/management/test_customer_unknown_fields.py
new file mode 100644
index 00000000000..235d5745791
--- /dev/null
+++ b/tests/integration/management/test_customer_unknown_fields.py
@@ -0,0 +1,55 @@
+import uuid
+from typing import Final
+
+import httpx
+import pytest
+
+from tests.integration._support.client import Gateway, Scenario
+
+pytestmark: Final = pytest.mark.shares_worker_state
+
+
+def _customer(scenario: Scenario, **fields: object) -> str:
+    customer: Final = f"integration-customer-{uuid.uuid4().hex}"
+    scenario.gateway.post("/customer/new", {"user_id": customer, **fields})  # pyright: ignore[reportArgumentType]  # JsonValue kwargs
+    scenario.cleanups.callback(scenario.gateway.post, "/customer/delete", {"user_ids": [customer]})
+    return customer
+
+
+def _post(gateway: Gateway, route: str, body: dict[str, object]) -> httpx.Response:
+    return gateway.request("POST", route, body)  # pyright: ignore[reportArgumentType]  # JsonValue body
+
+
+def _info(gateway: Gateway, customer: str) -> dict[str, object]:
+    return gateway.get("/customer/info", {"end_user_id": customer})
+
+
+@pytest.mark.parametrize(
+    ("body", "unknown_field"),
+    [
+        pytest.param({"tpm_limit": 5}, "tpm_limit", id="budget_field_on_update"),
+        pytest.param({"quota": {"opus": 1}}, "quota", id="made_up_field"),
+    ],
+)
+def test_customer_update_rejects_unknown_fields_and_leaves_the_customer_unchanged(
+    gateway: Gateway, body: dict[str, object], unknown_field: str
+) -> None:
+    with gateway.scenario() as scenario:
+        customer: Final = _customer(scenario, alias="before")
+        rejected: Final = _post(gateway, "/customer/update", {"user_id": customer, **body})
+        assert rejected.status_code == 422, rejected.text
+        assert unknown_field in rejected.text, rejected.text
+        assert _info(gateway, customer)["alias"] == "before"
+
+        accepted: Final = _post(gateway, "/customer/update", {"user_id": customer, "alias": "after"})
+        assert accepted.status_code == 200, accepted.text
+        assert _info(gateway, customer)["alias"] == "after"
+
+
+def test_customer_new_rejects_a_misspelled_field_and_creates_nothing(gateway: Gateway) -> None:
+    customer: Final = f"integration-customer-{uuid.uuid4().hex}"
+    rejected: Final = _post(gateway, "/customer/new", {"user_id": customer, "tpm_limti": 5})
+    assert rejected.status_code == 422, rejected.text
+    assert "tpm_limti" in rejected.text, rejected.text
+    missing: Final = gateway.request("GET", "/customer/info", params={"end_user_id": customer})
+    assert missing.status_code == 404, missing.text
diff --git a/tests/unit/proxy/management_endpoints/test_customer_budget.py b/tests/unit/proxy/management_endpoints/test_customer_budget.py
index 0beca0c15e8..ac172ac2ffb 100644
--- a/tests/unit/proxy/management_endpoints/test_customer_budget.py
+++ b/tests/unit/proxy/management_endpoints/test_customer_budget.py
@@ -144,7 +144,6 @@ async def test_update_customer_creates_budget_with_proper_relations(
     update_request = UpdateCustomerRequest(
         user_id="test-user",
         max_budget=100.0,  # This triggers budget creation
-        rpm_limit=200,  # Use valid budget field
     )
 
     # Act
@@ -267,7 +266,6 @@ async def test_update_customer_budget_creation_with_fallback_admin(
     update_request = UpdateCustomerRequest(
         user_id="test-user",
         max_budget=150.0,
-        tpm_limit=1000,  # Add another budget field
     )
 
     # Act
@@ -325,7 +323,6 @@ async def test_update_customer_with_budget_id_and_creation_fields(
         user_id="test-user",
         budget_id="existing-budget-link",  # For linking to existing budget
         max_budget=300.0,  # This should trigger new budget creation
-        rpm_limit=500,  # Use valid budget field
     )
 
     # Act
diff --git a/tests/unit/proxy/test__types.py b/tests/unit/proxy/test__types.py
index 40e66f1da65..1c97e9054ae 100644
--- a/tests/unit/proxy/test__types.py
+++ b/tests/unit/proxy/test__types.py
@@ -26,6 +26,7 @@ from litellm.proxy._types import (
     OrganizationMemberUpdateRequest,
     RegenerateKeyRequest,
     ResetSpendRequest,
+    UpdateCustomerRequest,
     UpdateKeyRequest,
     UpdateMCPServerRequest,
     UpdateTeamRequest,
@@ -634,3 +635,52 @@ def test_batch_file_caps_accept_only_positive_limits(setting):
         with pytest.raises(ValidationError):
             ConfigGeneralSettings.model_validate({setting: invalid})
     assert getattr(ConfigGeneralSettings.model_validate({setting: 3}), setting) == 3
+
+
+@pytest.mark.parametrize(
+    ("request_type", "body", "message"),
+    [
+        pytest.param(
+            UpdateCustomerRequest,
+            {"user_id": "acme", "tpm_limit": 5, "quota": {"opus": 1}},
+            "Unknown fields: quota, tpm_limit. tpm_limit: these live on the customer's budget object, "
+            "update it with /budget/update.",
+            id="update_with_a_budget_field_and_a_made_up_one",
+        ),
+        pytest.param(
+            UpdateCustomerRequest,
+            {"user_id": "acme", "alias": "Acme", "quota": 1},
+            "Unknown fields: quota.",
+            id="update_with_a_made_up_field_has_no_budget_hint",
+        ),
+        pytest.param(
+            NewCustomerRequest,
+            {"user_id": "acme", "tpm_limti": 5},
+            "Unknown fields: tpm_limti.",
+            id="create_with_a_misspelled_budget_field",
+        ),
+    ],
+)
+def test_a_customer_request_with_unknown_fields_is_refused_naming_them(
+    request_type: type[BaseModel], body: dict[str, object], message: str
+) -> None:
+    with pytest.raises(ValidationError) as exc:
+        request_type.model_validate(body)
+    assert [error["msg"] for error in exc.value.errors()] == [f"Value error, {message}"]
+
+
+@pytest.mark.parametrize(
+    ("request_type", "body"),
+    [
+        pytest.param(UpdateCustomerRequest, {"user_id": "acme", "alias": "Acme", "blocked": True}, id="update"),
+        pytest.param(
+            NewCustomerRequest,
+            {"user_id": "acme", "tpm_limit": 5, "model_tpm_limit": {"opus": 60}},
+            id="create_with_inline_budget_fields",
+        ),
+    ],
+)
+def test_a_customer_request_with_only_known_fields_is_accepted(
+    request_type: type[BaseModel], body: dict[str, object]
+) -> None:
+    assert request_type.model_validate(body).model_dump(exclude_unset=True) == body
diff --git a/ui/litellm-dashboard/src/lib/http/schema.d.ts b/ui/litellm-dashboard/src/lib/http/schema.d.ts
index b229461e981..e1b0104e089 100644
--- a/ui/litellm-dashboard/src/lib/http/schema.d.ts
+++ b/ui/litellm-dashboard/src/lib/http/schema.d.ts
@@ -4549,7 +4549,6 @@ export interface paths {
          *     - allowed_model_region: Optional[Union[Literal["eu"], Literal["us"]]] - Require all user requests to use models in this specific region.
          *     - default_model: Optional[str] - If no equivalent model in the allowed region, default all requests to this model.
          *     - models: Optional[list[str]] - Restrict this customer's access to the listed models.
-         *     - metadata: Optional[dict] = Metadata for customer, store information for customer. Example metadata = {"data_training_opt_out": True}
          *     - budget_duration: Optional[str] - Budget is reset at the end of specified duration. If not set, budget is never reset. You can set duration as seconds ("30s"), minutes ("30m"), hours ("30h"), days ("30d").
          *     - tpm_limit: Optional[int] - [Not Implemented Yet] Specify tpm limit for a given customer (Tokens per minute)
          *     - rpm_limit: Optional[int] - [Not Implemented Yet] Specify rpm limit for a given customer (Requests per minute)
@@ -4580,7 +4579,7 @@ export interface paths {
          *     ```
          *     curl --location 'http://0.0.0.0:4000/customer/new'         --header "Authorization: Bearer $LITELLM_MASTER_KEY"         --header 'Content-Type: application/json'         --data '{
          *             "user_id" : "ishaan-jaff-3",
-         *             "allowed_region": "eu",
+         *             "allowed_model_region": "eu",
          *             "budget_id": "free_tier",
          *             "models": ["gpt-4o-mini"],
          *             "default_model": "azure/gpt-3.5-turbo-eu"
@@ -5229,7 +5228,6 @@ export interface paths {
          *     - allowed_model_region: Optional[Union[Literal["eu"], Literal["us"]]] - Require all user requests to use models in this specific region.
          *     - default_model: Optional[str] - If no equivalent model in the allowed region, default all requests to this model.
          *     - models: Optional[list[str]] - Restrict this customer's access to the listed models.
-         *     - metadata: Optional[dict] = Metadata for customer, store information for customer. Example metadata = {"data_training_opt_out": True}
          *     - budget_duration: Optional[str] - Budget is reset at the end of specified duration. If not set, budget is never reset. You can set duration as seconds ("30s"), minutes ("30m"), hours ("30h"), days ("30d").
          *     - tpm_limit: Optional[int] - [Not Implemented Yet] Specify tpm limit for a given customer (Tokens per minute)
          *     - rpm_limit: Optional[int] - [Not Implemented Yet] Specify rpm limit for a given customer (Requests per minute)
@@ -5260,7 +5258,7 @@ export interface paths {
          *     ```
          *     curl --location 'http://0.0.0.0:4000/customer/new'         --header "Authorization: Bearer $LITELLM_MASTER_KEY"         --header 'Content-Type: application/json'         --data '{
          *             "user_id" : "ishaan-jaff-3",
-         *             "allowed_region": "eu",
+         *             "allowed_model_region": "eu",
          *             "budget_id": "free_tier",
          *             "models": ["gpt-4o-mini"],
          *             "default_model": "azure/gpt-3.5-turbo-eu"