Add GET list of providers endpoint (#16432)

docs/my-website/docs/proxy/model_hub.md

@@ -37,3 +37,17 @@ Click on `Make Public` and select the models you want to expose.
 Go to the public url (`PROXY_BASE_URL/ui/model_hub_table`) and see available models. 
 
 <Image img={require('../../img/final_public_model_hub_view.png')} />  
+
+## API Endpoints
+
+LiteLLM also exposes REST endpoints:
+
+- `GET /public/model_hub` – returns the list of public model groups. Requires a valid user API key.
+- `GET /public/model_hub/info` – returns metadata (docs title, version, useful links) for the public model hub.
+- `GET /public/providers` – returns a sorted list of all providers supported by LiteLLM. No authentication required.
+
+Example:
+
+```bash
+curl -s PROXY_BASE_URL/public/providers | jq
+```

litellm/proxy/public_endpoints/public_endpoints.py

@@ -8,6 +8,7 @@ from litellm.types.proxy.management_endpoints.model_management_endpoints import
     ModelGroupInfoProxy,
 )
 from litellm.types.proxy.public_endpoints.public_endpoints import PublicModelHubInfo
+from litellm.types.utils import LlmProviders
 
 router = APIRouter()
 
@@ -60,3 +61,16 @@ async def public_model_hub_info():
         litellm_version=version,
         useful_links=litellm.public_model_groups_links,
     )
+
+
+@router.get(
+    "/public/providers",
+    tags=["public", "providers"],
+    response_model=List[str],
+)
+async def get_supported_providers() -> List[str]:
+    """
+    Return a sorted list of all providers supported by LiteLLM.
+    """
+
+    return sorted(provider.value for provider in LlmProviders)

tests/test_litellm/proxy/public_endpoints/test_public_endpoints.py

@@ -0,0 +1,25 @@
+import os
+import sys
+
+sys.path.insert(
+    0, os.path.abspath("../../..")
+)
+
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+from litellm.proxy.public_endpoints import router
+from litellm.types.utils import LlmProviders
+
+
+def test_get_supported_providers_returns_enum_values():
+    app = FastAPI()
+    app.include_router(router)
+    client = TestClient(app)
+
+    response = client.get("/public/providers")
+
+    assert response.status_code == 200
+    expected_providers = sorted(provider.value for provider in LlmProviders)
+    assert response.json() == expected_providers
+