fix(azure): skip /v1 and api-version when baseURL is provided

.changeset/fix-azure-baseurl-no-v1.md

@@ -0,0 +1,12 @@
+---
+'@ai-sdk/azure': patch
+---
+
+fix(azure): skip /v1 path segment and api-version query param when baseURL is provided
+
+When `createAzure({ baseURL: '...' })` is used, the provider now constructs
+`{baseURL}{path}` instead of `{baseURL}/v1{path}?api-version=...`. This allows
+custom API gateways and proxies that handle routing internally to work without
+receiving unexpected path segments or query parameters.
+
+Closes #13956. Also fixes the api-version issue reported in #14009.

packages/azure/src/azure-openai-provider.test.ts

@@ -89,6 +89,9 @@ const server = createTestServer({
   'https://test-resource.openai.azure.com/openai/v1/audio/speech': {},
   'https://test-resource.openai.azure.com/openai/deployments/whisper-1/audio/transcriptions':
     {},
+  'https://test-resource.openai.azure.com/openai/responses': {},
+  'https://test-resource.openai.azure.com/openai/chat/completions': {},
+  'https://test-resource.openai.azure.com/openai/images/generations': {},
 });
 
 describe('responses (default language model)', () => {
@@ -187,8 +190,14 @@ describe('responses (default language model)', () => {
       );
     });
 
-    it('should use the baseURL correctly', async () => {
+    it('should use the baseURL without appending /v1 or api-version', async () => {
       prepareJsonResponse();
+      server.urls[
+        'https://test-resource.openai.azure.com/openai/responses'
+      ].response =
+        server.urls[
+          'https://test-resource.openai.azure.com/openai/v1/responses'
+        ].response;
 
       const provider = createAzure({
         baseURL: 'https://test-resource.openai.azure.com/openai',
@@ -199,8 +208,11 @@ describe('responses (default language model)', () => {
         prompt: TEST_PROMPT,
       });
       expect(server.calls[0].requestUrl).toMatchInlineSnapshot(
-        `"https://test-resource.openai.azure.com/openai/v1/responses?api-version=v1"`,
+        `"https://test-resource.openai.azure.com/openai/responses"`,
       );
+      expect(
+        server.calls[0].requestUrlSearchParams.get('api-version'),
+      ).toBeNull();
     });
   });
 });
@@ -292,8 +304,14 @@ describe('chat', () => {
       );
     });
 
-    it('should use the baseURL correctly', async () => {
+    it('should use the baseURL without appending /v1 or api-version', async () => {
       prepareJsonResponse();
+      server.urls[
+        'https://test-resource.openai.azure.com/openai/chat/completions'
+      ].response =
+        server.urls[
+          'https://test-resource.openai.azure.com/openai/v1/chat/completions'
+        ].response;
 
       const provider = createAzure({
         baseURL: 'https://test-resource.openai.azure.com/openai',
@@ -304,8 +322,11 @@ describe('chat', () => {
         prompt: TEST_PROMPT,
       });
       expect(server.calls[0].requestUrl).toMatchInlineSnapshot(
-        `"https://test-resource.openai.azure.com/openai/v1/chat/completions?api-version=v1"`,
+        `"https://test-resource.openai.azure.com/openai/chat/completions"`,
       );
+      expect(
+        server.calls[0].requestUrlSearchParams.get('api-version'),
+      ).toBeNull();
     });
   });
 });
@@ -650,8 +671,14 @@ describe('image', () => {
       );
     });
 
-    it('should use the baseURL correctly', async () => {
+    it('should use the baseURL without appending /v1 or api-version', async () => {
       prepareJsonResponse();
+      server.urls[
+        'https://test-resource.openai.azure.com/openai/images/generations'
+      ].response =
+        server.urls[
+          'https://test-resource.openai.azure.com/openai/v1/images/generations'
+        ].response;
 
       const provider = createAzure({
         baseURL: 'https://test-resource.openai.azure.com/openai',
@@ -670,8 +697,11 @@ describe('image', () => {
       });
 
       expect(server.calls[0].requestUrl).toMatchInlineSnapshot(
-        `"https://test-resource.openai.azure.com/openai/v1/images/generations?api-version=v1"`,
+        `"https://test-resource.openai.azure.com/openai/images/generations"`,
       );
+      expect(
+        server.calls[0].requestUrlSearchParams.get('api-version'),
+      ).toBeNull();
     });
 
     it('should extract the generated images', async () => {
@@ -873,8 +903,14 @@ describe('responses', () => {
       );
     });
 
-    it('should use the baseURL correctly', async () => {
+    it('should use the baseURL without appending /v1 or api-version', async () => {
       prepareJsonFixtureResponse('azure-text.1');
+      server.urls[
+        'https://test-resource.openai.azure.com/openai/responses'
+      ].response =
+        server.urls[
+          'https://test-resource.openai.azure.com/openai/v1/responses'
+        ].response;
 
       const provider = createAzure({
         baseURL: 'https://test-resource.openai.azure.com/openai',
@@ -886,8 +922,11 @@ describe('responses', () => {
       });
 
       expect(server.calls[0].requestUrl).toMatchInlineSnapshot(
-        `"https://test-resource.openai.azure.com/openai/v1/responses?api-version=v1"`,
+        `"https://test-resource.openai.azure.com/openai/responses"`,
       );
+      expect(
+        server.calls[0].requestUrlSearchParams.get('api-version'),
+      ).toBeNull();
     });
 
     it('should handle Azure file IDs with assistant- prefix', async () => {

packages/azure/src/azure-openai-provider.ts

@@ -105,7 +105,9 @@ export interface AzureOpenAIProviderSettings {
    * Use a different URL prefix for API calls, e.g. to use proxy servers. Either this or `resourceName` can be used.
    * When a baseURL is provided, the resourceName is ignored.
    *
-   * With a baseURL, the resolved URL is `{baseURL}/v1{path}`.
+   * With a baseURL, the resolved URL is `{baseURL}{path}` — no `/v1` is appended and no
+   * `api-version` query parameter is added. This allows custom gateways and proxies that
+   * handle routing internally to receive the URL exactly as provided.
    */
   baseURL?: string;
 
@@ -174,12 +176,18 @@ export function createAzure(
     if (options.useDeploymentBasedUrls) {
       // Use deployment-based format for compatibility with certain Azure OpenAI models
       fullUrl = new URL(`${baseUrlPrefix}/deployments/${modelId}${path}`);
+    } else if (options.baseURL) {
+      // When baseURL is explicitly provided, use it as-is without appending /v1.
+      // Callers using a custom gateway or proxy control the URL shape themselves.
+      fullUrl = new URL(`${baseUrlPrefix}${path}`);
     } else {
       // Use v1 API format - no deployment ID in URL
       fullUrl = new URL(`${baseUrlPrefix}/v1${path}`);
     }
 
-    fullUrl.searchParams.set('api-version', apiVersion);
+    if (!options.baseURL) {
+      fullUrl.searchParams.set('api-version', apiVersion);
+    }
     return fullUrl.toString();
   };