fix(azure): support v1/preview/latest API versions

When using api_version="v1", "preview", or "latest", the Azure OpenAI
client now correctly constructs URLs using the new /openai/v1/ path
format instead of the legacy /openai/deployments/{model}/ format.

The new Azure OpenAI v1 API uses a different URL structure:
- Old: /openai/deployments/{model}/chat/completions?api-version=2024-10-21
- New: /openai/v1/chat/completions?api-version=v1

Changes:
- Add _is_v1_api flag to BaseAzureClient
- Skip adding /deployments/{model}/ path for v1 API in _build_request
- Use /openai/v1/ base URL for v1/preview/latest api_version values
- Add comprehensive tests for v1 API support

Author: Chesars

src/openai/lib/azure.py

@@ -52,6 +52,7 @@ def __init__(self) -> None:
 class BaseAzureClient(BaseClient[_HttpxClientT, _DefaultStreamT]):
     _azure_endpoint: httpx.URL | None
     _azure_deployment: str | None
+    _is_v1_api: bool
 
     @override
     def _build_request(
@@ -60,10 +61,12 @@ def _build_request(
         *,
         retries_taken: int = 0,
     ) -> httpx.Request:
-        if options.url in _deployments_endpoints and is_mapping(options.json_data):
-            model = options.json_data.get("model")
-            if model is not None and "/deployments" not in str(self.base_url.path):
-                options.url = f"/deployments/{model}{options.url}"
+        # v1 API doesn't use /deployments/{model}/ path - model is passed in body
+        if not getattr(self, '_is_v1_api', False):
+            if options.url in _deployments_endpoints and is_mapping(options.json_data):
+                model = options.json_data.get("model")
+                if model is not None and "/deployments" not in str(self.base_url.path):
+                    options.url = f"/deployments/{model}{options.url}"
 
         return super()._build_request(options, retries_taken=retries_taken)
 
@@ -208,6 +211,9 @@ def __init__(
                 "Must provide either the `api_version` argument or the `OPENAI_API_VERSION` environment variable"
             )
 
+        # Check if using v1 API format (new Azure OpenAI API)
+        _is_v1_api = api_version in ("v1", "latest", "preview")
+
         if default_query is None:
             default_query = {"api-version": api_version}
         else:
@@ -222,7 +228,10 @@ def __init__(
                     "Must provide one of the `base_url` or `azure_endpoint` arguments, or the `AZURE_OPENAI_ENDPOINT` environment variable"
                 )
 
-            if azure_deployment is not None:
+            if _is_v1_api:
+                # v1 API uses /openai/v1/ path without /deployments/
+                base_url = f"{azure_endpoint.rstrip('/')}/openai/v1"
+            elif azure_deployment is not None:
                 base_url = f"{azure_endpoint.rstrip('/')}/openai/deployments/{azure_deployment}"
             else:
                 base_url = f"{azure_endpoint.rstrip('/')}/openai"
@@ -253,6 +262,7 @@ def __init__(
         self._azure_ad_token_provider = azure_ad_token_provider
         self._azure_deployment = azure_deployment if azure_endpoint else None
         self._azure_endpoint = httpx.URL(azure_endpoint) if azure_endpoint else None
+        self._is_v1_api = _is_v1_api
 
     @override
     def copy(
@@ -489,6 +499,9 @@ def __init__(
                 "Must provide either the `api_version` argument or the `OPENAI_API_VERSION` environment variable"
             )
 
+        # Check if using v1 API format (new Azure OpenAI API)
+        _is_v1_api = api_version in ("v1", "latest", "preview")
+
         if default_query is None:
             default_query = {"api-version": api_version}
         else:
@@ -503,7 +516,10 @@ def __init__(
                     "Must provide one of the `base_url` or `azure_endpoint` arguments, or the `AZURE_OPENAI_ENDPOINT` environment variable"
                 )
 
-            if azure_deployment is not None:
+            if _is_v1_api:
+                # v1 API uses /openai/v1/ path without /deployments/
+                base_url = f"{azure_endpoint.rstrip('/')}/openai/v1"
+            elif azure_deployment is not None:
                 base_url = f"{azure_endpoint.rstrip('/')}/openai/deployments/{azure_deployment}"
             else:
                 base_url = f"{azure_endpoint.rstrip('/')}/openai"
@@ -534,6 +550,7 @@ def __init__(
         self._azure_ad_token_provider = azure_ad_token_provider
         self._azure_deployment = azure_deployment if azure_endpoint else None
         self._azure_endpoint = httpx.URL(azure_endpoint) if azure_endpoint else None
+        self._is_v1_api = _is_v1_api
 
     @override
     def copy(

tests/lib/test_azure.py

@@ -802,3 +802,88 @@ def test_client_sets_base_url(client: Client) -> None:
         )
     )
     assert req.url == "https://example-resource.azure.openai.com/openai/models?api-version=2024-02-01"
+
+
+# Tests for v1 API support
+class TestAzureV1API:
+    """Tests for Azure OpenAI v1/latest/preview API support."""
+
+    @pytest.mark.parametrize("api_version", ["v1", "latest", "preview"])
+    @pytest.mark.parametrize("client_cls", [AzureOpenAI, AsyncAzureOpenAI])
+    def test_v1_api_base_url(self, api_version: str, client_cls: type[Client]) -> None:
+        """v1 API should use /openai/v1/ base URL."""
+        client = client_cls(
+            api_version=api_version,
+            api_key="test",
+            azure_endpoint="https://example.azure.openai.com",
+        )
+        assert "/openai/v1" in str(client.base_url)
+        assert "/deployments/" not in str(client.base_url)
+
+    @pytest.mark.parametrize("api_version", ["v1", "latest", "preview"])
+    @pytest.mark.parametrize("client_cls", [AzureOpenAI, AsyncAzureOpenAI])
+    def test_v1_api_no_deployments_path(self, api_version: str, client_cls: type[Client]) -> None:
+        """v1 API should NOT add /deployments/{model}/ to the path."""
+        client = client_cls(
+            api_version=api_version,
+            api_key="test",
+            azure_endpoint="https://example.azure.openai.com",
+        )
+        req = client._build_request(
+            FinalRequestOptions.construct(
+                method="post",
+                url="/chat/completions",
+                json_data={"model": "gpt-4o"},
+            )
+        )
+        assert "/deployments/" not in str(req.url)
+        assert "/openai/v1/chat/completions" in str(req.url)
+
+    @pytest.mark.parametrize("api_version", ["v1", "latest", "preview"])
+    @pytest.mark.parametrize("client_cls", [AzureOpenAI, AsyncAzureOpenAI])
+    def test_v1_api_has_query_param(self, api_version: str, client_cls: type[Client]) -> None:
+        """v1 API should still include ?api-version= query param."""
+        client = client_cls(
+            api_version=api_version,
+            api_key="test",
+            azure_endpoint="https://example.azure.openai.com",
+        )
+        req = client._build_request(
+            FinalRequestOptions.construct(
+                method="post",
+                url="/chat/completions",
+                json_data={"model": "gpt-4o"},
+            )
+        )
+        assert f"api-version={api_version}" in str(req.url)
+
+    @pytest.mark.parametrize("client_cls", [AzureOpenAI, AsyncAzureOpenAI])
+    def test_traditional_api_still_works(self, client_cls: type[Client]) -> None:
+        """Traditional API should still use /deployments/ path."""
+        client = client_cls(
+            api_version="2024-10-21",
+            api_key="test",
+            azure_endpoint="https://example.azure.openai.com",
+        )
+        req = client._build_request(
+            FinalRequestOptions.construct(
+                method="post",
+                url="/chat/completions",
+                json_data={"model": "gpt-4o"},
+            )
+        )
+        assert "/deployments/gpt-4o/" in str(req.url)
+        assert "api-version=2024-10-21" in str(req.url)
+
+    @pytest.mark.parametrize("api_version", ["v1", "latest", "preview"])
+    def test_v1_api_ignores_azure_deployment_param(self, api_version: str) -> None:
+        """v1 API should ignore azure_deployment parameter since model is in body."""
+        client = AzureOpenAI(
+            api_version=api_version,
+            api_key="test",
+            azure_endpoint="https://example.azure.openai.com",
+            azure_deployment="ignored-deployment",
+        )
+        # base_url should still be /openai/v1, not /openai/deployments/ignored-deployment
+        assert "/openai/v1" in str(client.base_url)
+        assert "/deployments/" not in str(client.base_url)