diff --git a/sdk/openai/azure-ai-openai/src/main/java/com/azure/ai/openai/OpenAIClientBuilder.java b/sdk/openai/azure-ai-openai/src/main/java/com/azure/ai/openai/OpenAIClientBuilder.java
index 151f613e1fa2..121ab89c37dc 100644
--- a/sdk/openai/azure-ai-openai/src/main/java/com/azure/ai/openai/OpenAIClientBuilder.java
+++ b/sdk/openai/azure-ai-openai/src/main/java/com/azure/ai/openai/OpenAIClientBuilder.java
@@ -3,7 +3,7 @@
 // Code generated by Microsoft (R) TypeSpec Code Generator.
 package com.azure.ai.openai;
 
-import static com.azure.ai.openai.implementation.NonAzureOpenAIClientImpl.OPEN_AI_ENDPOINT;
+import static com.azure.ai.openai.implementation.NonAzureOpenAIClientImpl.OPEN_AI_ENDPOINT_PATTERN;
 
 import com.azure.ai.openai.implementation.NonAzureOpenAIClientImpl;
 import com.azure.ai.openai.implementation.OpenAIClientImpl;
@@ -333,7 +333,7 @@ private HttpPipeline createHttpPipeline() {
     private NonAzureOpenAIClientImpl buildInnerNonAzureOpenAIClient() {
         HttpPipeline localPipeline = (pipeline != null) ? pipeline : createHttpPipeline();
         NonAzureOpenAIClientImpl client
-            = new NonAzureOpenAIClientImpl(localPipeline, JacksonAdapter.createDefaultSerializerAdapter());
+            = new NonAzureOpenAIClientImpl(localPipeline, JacksonAdapter.createDefaultSerializerAdapter(), endpoint);
         return client;
     }
 
@@ -362,11 +362,11 @@ public OpenAIClient buildClient() {
     private static final ClientLogger LOGGER = new ClientLogger(OpenAIClientBuilder.class);
 
     /**
-     * OpenAI service can be used by either not setting the endpoint or by setting the endpoint to start with
-     * "https://api.openai.com/"
+     * OpenAI service can be used by either not setting the endpoint or by setting the endpoint to a
+     * URL like "https://api.openai.com/v1" or "https://eu.api.openai.com/v1".
      */
     private boolean useNonAzureOpenAIService() {
-        return endpoint == null || endpoint.startsWith(OPEN_AI_ENDPOINT);
+        return endpoint == null || OPEN_AI_ENDPOINT_PATTERN.matcher(endpoint).matches();
     }
 
     private void validateClient() {
diff --git a/sdk/openai/azure-ai-openai/src/main/java/com/azure/ai/openai/implementation/NonAzureOpenAIClientImpl.java b/sdk/openai/azure-ai-openai/src/main/java/com/azure/ai/openai/implementation/NonAzureOpenAIClientImpl.java
index 940766d2e8f8..d84bb2b5a626 100644
--- a/sdk/openai/azure-ai-openai/src/main/java/com/azure/ai/openai/implementation/NonAzureOpenAIClientImpl.java
+++ b/sdk/openai/azure-ai-openai/src/main/java/com/azure/ai/openai/implementation/NonAzureOpenAIClientImpl.java
@@ -28,6 +28,7 @@
 import com.azure.core.util.Context;
 import com.azure.core.util.FluxUtil;
 import com.azure.core.util.serializer.SerializerAdapter;
+import java.util.regex.Pattern;
 import reactor.core.publisher.Mono;
 
 import java.util.Map;
@@ -55,7 +56,7 @@ public HttpPipeline getHttpPipeline() {
     private final SerializerAdapter serializerAdapter;
 
     /**
-     * Gets The serializer to serialize an object into a string.
+     * Gets the serializer to serialize an object into a string.
      *
      * @return the serializerAdapter value.
      */
@@ -63,20 +64,39 @@ public SerializerAdapter getSerializerAdapter() {
         return this.serializerAdapter;
     }
 
+    /** The endpoint to send API requests to. */
+    private final String endpoint;
+
     /**
-     * This is the endpoint that non-azure OpenAI supports. Currently, it has only v1 version.
+     * Gets the endpoint that this client is configured to send requests to.
+     *
+     * @return the endpoint value.
+     */
+    public String getEndpoint() {
+        return this.endpoint;
+    }
+
+    /**
+     * This is the generic endpoint that non-azure OpenAI supports. Currently, it has only v1 version.
      */
     public static final String OPEN_AI_ENDPOINT = "https://api.openai.com/v1";
 
+    /**
+     * Pattern for validating native OpenAI API endpoint URLs. This allows for subdomains to support
+     * regional endpoints.
+     */
+    public static final Pattern OPEN_AI_ENDPOINT_PATTERN = Pattern.compile("https://(\\w*\\.)?api\\.openai\\.com/v1");
+
     /**
      * Initializes an instance of OpenAIClient client.
      *
      * @param httpPipeline The HTTP pipeline to send requests through.
      * @param serializerAdapter The serializer to serialize an object into a string.
      */
-    public NonAzureOpenAIClientImpl(HttpPipeline httpPipeline, SerializerAdapter serializerAdapter) {
+    public NonAzureOpenAIClientImpl(HttpPipeline httpPipeline, SerializerAdapter serializerAdapter, String endpoint) {
         this.httpPipeline = httpPipeline;
         this.serializerAdapter = serializerAdapter;
+        this.endpoint = endpoint == null ? OPEN_AI_ENDPOINT : endpoint;
         this.service
             = RestProxy.create(NonAzureOpenAIClientService.class, this.httpPipeline, this.getSerializerAdapter());
     }
@@ -587,8 +607,8 @@ public Mono<Response<BinaryData>> getEmbeddingsWithResponseAsync(String modelId,
         final String accept = "application/json";
         // modelId is part of the request body in nonAzure OpenAI
         final BinaryData embeddingsOptionsUpdated = addModelIdJson(embeddingsOptions, modelId);
-        return FluxUtil.withContext(context -> service.getEmbeddings(OPEN_AI_ENDPOINT, accept, embeddingsOptionsUpdated,
-            requestOptions, context));
+        return FluxUtil.withContext(
+            context -> service.getEmbeddings(getEndpoint(), accept, embeddingsOptionsUpdated, requestOptions, context));
     }
 
     /**
@@ -644,8 +664,7 @@ public Response<BinaryData> getEmbeddingsWithResponse(String modelId, BinaryData
         final String accept = "application/json";
         // modelId is part of the request body in nonAzure OpenAI
         final BinaryData embeddingsOptionsUpdated = addModelIdJson(embeddingsOptions, modelId);
-        return service.getEmbeddingsSync(OPEN_AI_ENDPOINT, accept, embeddingsOptionsUpdated, requestOptions,
-            Context.NONE);
+        return service.getEmbeddingsSync(getEndpoint(), accept, embeddingsOptionsUpdated, requestOptions, Context.NONE);
     }
 
     /**
@@ -736,8 +755,8 @@ public Mono<Response<BinaryData>> getCompletionsWithResponseAsync(String modelId
         final String accept = "application/json";
         // modelId is part of the request body in nonAzure OpenAI
         final BinaryData completionsOptionsUpdated = addModelIdJson(completionsOptions, modelId);
-        return FluxUtil.withContext(context -> service.getCompletions(OPEN_AI_ENDPOINT, accept,
-            completionsOptionsUpdated, requestOptions, context));
+        return FluxUtil.withContext(context -> service.getCompletions(getEndpoint(), accept, completionsOptionsUpdated,
+            requestOptions, context));
     }
 
     /**
@@ -826,7 +845,7 @@ public Response<BinaryData> getCompletionsWithResponse(String modelId, BinaryDat
         final String accept = "application/json";
         // modelId is part of the request body in nonAzure OpenAI
         final BinaryData completionsOptionsUpdated = addModelIdJson(completionsOptions, modelId);
-        return service.getCompletionsSync(OPEN_AI_ENDPOINT, accept, completionsOptionsUpdated, requestOptions,
+        return service.getCompletionsSync(getEndpoint(), accept, completionsOptionsUpdated, requestOptions,
             Context.NONE);
     }
 
@@ -909,7 +928,7 @@ public Mono<Response<BinaryData>> getChatCompletionsWithResponseAsync(String mod
         final String accept = "application/json";
         // modelId is part of the request body in nonAzure OpenAI
         final BinaryData chatCompletionsOptionsUpdated = addModelIdJson(chatCompletionsOptions, modelId);
-        return FluxUtil.withContext(context -> service.getChatCompletions(OPEN_AI_ENDPOINT, accept,
+        return FluxUtil.withContext(context -> service.getChatCompletions(getEndpoint(), accept,
             chatCompletionsOptionsUpdated, requestOptions, context));
     }
 
@@ -991,7 +1010,7 @@ public Response<BinaryData> getChatCompletionsWithResponse(String modelId, Binar
         final String accept = "application/json";
         // modelId is part of the request body in nonAzure OpenAI
         final BinaryData chatCompletionsOptionsUpdated = addModelIdJson(chatCompletionsOptions, modelId);
-        return service.getChatCompletionsSync(OPEN_AI_ENDPOINT, accept, chatCompletionsOptionsUpdated, requestOptions,
+        return service.getChatCompletionsSync(getEndpoint(), accept, chatCompletionsOptionsUpdated, requestOptions,
             Context.NONE);
     }
 
@@ -1044,7 +1063,7 @@ public Mono<Response<BinaryData>> getImageGenerationsWithResponseAsync(String mo
         final String accept = "application/json";
         // modelId is part of the request body in nonAzure OpenAI
         final BinaryData imageGenerationOptionsUpdated = addModelIdJson(imageGenerationOptions, modelId);
-        return FluxUtil.withContext(context -> service.getImageGenerations(OPEN_AI_ENDPOINT, accept,
+        return FluxUtil.withContext(context -> service.getImageGenerations(getEndpoint(), accept,
             imageGenerationOptionsUpdated, requestOptions, context));
     }
 
@@ -1096,7 +1115,7 @@ public Response<BinaryData> getImageGenerationsWithResponse(String modelId, Bina
         RequestOptions requestOptions) {
         final String accept = "application/json";
         final BinaryData imageGenerationOptionsUpdated = addModelIdJson(imageGenerationOptions, modelId);
-        return service.getImageGenerationsSync(OPEN_AI_ENDPOINT, accept, imageGenerationOptionsUpdated, requestOptions,
+        return service.getImageGenerationsSync(getEndpoint(), accept, imageGenerationOptionsUpdated, requestOptions,
             Context.NONE);
     }
 
@@ -1175,7 +1194,7 @@ public static BinaryData addModelIdJson(BinaryData inputJson, String modelId) {
     public Mono<Response<BinaryData>> getAudioTranscriptionAsResponseObjectWithResponseAsync(String modelId,
         BinaryData audioTranscriptionOptions, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return FluxUtil.withContext(context -> service.getAudioTranscriptionAsResponseObject(OPEN_AI_ENDPOINT, accept,
+        return FluxUtil.withContext(context -> service.getAudioTranscriptionAsResponseObject(getEndpoint(), accept,
             audioTranscriptionOptions, requestOptions, context));
     }
 
@@ -1236,7 +1255,7 @@ public Mono<Response<BinaryData>> getAudioTranscriptionAsResponseObjectWithRespo
     public Response<BinaryData> getAudioTranscriptionAsResponseObjectWithResponse(String modelId,
         BinaryData audioTranscriptionOptions, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.getAudioTranscriptionAsResponseObjectSync(OPEN_AI_ENDPOINT, accept, audioTranscriptionOptions,
+        return service.getAudioTranscriptionAsResponseObjectSync(getEndpoint(), accept, audioTranscriptionOptions,
             requestOptions, Context.NONE);
     }
 
@@ -1277,7 +1296,7 @@ public Response<BinaryData> getAudioTranscriptionAsResponseObjectWithResponse(St
     public Mono<Response<BinaryData>> getAudioTranscriptionAsPlainTextWithResponseAsync(String modelId,
         BinaryData audioTranscriptionOptions, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return FluxUtil.withContext(context -> service.getAudioTranscriptionAsPlainText(OPEN_AI_ENDPOINT, accept,
+        return FluxUtil.withContext(context -> service.getAudioTranscriptionAsPlainText(getEndpoint(), accept,
             audioTranscriptionOptions, requestOptions, context));
     }
 
@@ -1317,7 +1336,7 @@ public Mono<Response<BinaryData>> getAudioTranscriptionAsPlainTextWithResponseAs
     public Response<BinaryData> getAudioTranscriptionAsPlainTextWithResponse(String modelId,
         BinaryData audioTranscriptionOptions, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.getAudioTranscriptionAsPlainTextSync(OPEN_AI_ENDPOINT, accept, audioTranscriptionOptions,
+        return service.getAudioTranscriptionAsPlainTextSync(getEndpoint(), accept, audioTranscriptionOptions,
             requestOptions, Context.NONE);
     }
 
@@ -1377,7 +1396,7 @@ public Response<BinaryData> getAudioTranscriptionAsPlainTextWithResponse(String
     public Mono<Response<BinaryData>> getAudioTranslationAsResponseObjectWithResponseAsync(String deploymentOrModelName,
         BinaryData audioTranslationOptions, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return FluxUtil.withContext(context -> service.getAudioTranslationAsResponseObject(OPEN_AI_ENDPOINT, accept,
+        return FluxUtil.withContext(context -> service.getAudioTranslationAsResponseObject(getEndpoint(), accept,
             audioTranslationOptions, requestOptions, context));
     }
 
@@ -1437,7 +1456,7 @@ public Mono<Response<BinaryData>> getAudioTranslationAsResponseObjectWithRespons
     public Response<BinaryData> getAudioTranslationAsResponseObjectWithResponse(String modelId,
         BinaryData audioTranslationOptions, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.getAudioTranslationAsResponseObjectSync(OPEN_AI_ENDPOINT, accept, audioTranslationOptions,
+        return service.getAudioTranslationAsResponseObjectSync(getEndpoint(), accept, audioTranslationOptions,
             requestOptions, Context.NONE);
     }
 
@@ -1476,7 +1495,7 @@ public Response<BinaryData> getAudioTranslationAsResponseObjectWithResponse(Stri
     public Mono<Response<BinaryData>> getAudioTranslationAsPlainTextWithResponseAsync(String modelId,
         BinaryData audioTranslationOptions, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return FluxUtil.withContext(context -> service.getAudioTranslationAsPlainText(OPEN_AI_ENDPOINT, accept,
+        return FluxUtil.withContext(context -> service.getAudioTranslationAsPlainText(getEndpoint(), accept,
             audioTranslationOptions, requestOptions, context));
     }
 
@@ -1515,7 +1534,7 @@ public Mono<Response<BinaryData>> getAudioTranslationAsPlainTextWithResponseAsyn
     public Response<BinaryData> getAudioTranslationAsPlainTextWithResponse(String modelId,
         BinaryData audioTranslationOptions, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.getAudioTranslationAsPlainTextSync(OPEN_AI_ENDPOINT, accept, audioTranslationOptions,
+        return service.getAudioTranslationAsPlainTextSync(getEndpoint(), accept, audioTranslationOptions,
             requestOptions, Context.NONE);
     }
 
@@ -1553,7 +1572,7 @@ public Response<BinaryData> getAudioTranslationAsPlainTextWithResponse(String mo
     public Mono<Response<BinaryData>> generateSpeechFromTextWithResponseAsync(String modelId,
         BinaryData speechGenerationOptions, RequestOptions requestOptions) {
         final String accept = "application/octet-stream, application/json";
-        return FluxUtil.withContext(context -> service.generateSpeechFromText(OPEN_AI_ENDPOINT, accept,
+        return FluxUtil.withContext(context -> service.generateSpeechFromText(getEndpoint(), accept,
             speechGenerationOptions, requestOptions, context));
     }
 
@@ -1590,7 +1609,7 @@ public Mono<Response<BinaryData>> generateSpeechFromTextWithResponseAsync(String
     public Response<BinaryData> generateSpeechFromTextWithResponse(BinaryData speechGenerationOptions,
         RequestOptions requestOptions) {
         final String accept = "application/octet-stream, application/json";
-        return service.generateSpeechFromTextSync(OPEN_AI_ENDPOINT, accept, speechGenerationOptions, requestOptions,
+        return service.generateSpeechFromTextSync(getEndpoint(), accept, speechGenerationOptions, requestOptions,
             Context.NONE);
     }
 
@@ -1635,7 +1654,7 @@ public Response<BinaryData> generateSpeechFromTextWithResponse(BinaryData speech
     @ServiceMethod(returns = ReturnType.SINGLE)
     public Mono<Response<BinaryData>> listFilesWithResponseAsync(RequestOptions requestOptions) {
         final String accept = "application/json";
-        return FluxUtil.withContext(context -> service.listFiles(OPEN_AI_ENDPOINT, accept, requestOptions, context));
+        return FluxUtil.withContext(context -> service.listFiles(getEndpoint(), accept, requestOptions, context));
     }
 
     /**
@@ -1679,7 +1698,7 @@ public Mono<Response<BinaryData>> listFilesWithResponseAsync(RequestOptions requ
     @ServiceMethod(returns = ReturnType.SINGLE)
     public Response<BinaryData> listFilesWithResponse(RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.listFilesSync(OPEN_AI_ENDPOINT, accept, requestOptions, Context.NONE);
+        return service.listFilesSync(getEndpoint(), accept, requestOptions, Context.NONE);
     }
 
     /**
@@ -1713,8 +1732,8 @@ public Mono<Response<BinaryData>> uploadFileWithResponseAsync(BinaryData uploadF
         RequestOptions requestOptions) {
         final String contentType = "multipart/form-data";
         final String accept = "application/json";
-        return FluxUtil.withContext(context -> service.uploadFile(OPEN_AI_ENDPOINT, contentType, accept,
-            uploadFileRequest, requestOptions, context));
+        return FluxUtil.withContext(context -> service.uploadFile(getEndpoint(), contentType, accept, uploadFileRequest,
+            requestOptions, context));
     }
 
     /**
@@ -1746,7 +1765,7 @@ public Mono<Response<BinaryData>> uploadFileWithResponseAsync(BinaryData uploadF
     public Response<BinaryData> uploadFileWithResponse(BinaryData uploadFileRequest, RequestOptions requestOptions) {
         final String contentType = "multipart/form-data";
         final String accept = "application/json";
-        return service.uploadFileSync(OPEN_AI_ENDPOINT, contentType, accept, uploadFileRequest, requestOptions,
+        return service.uploadFileSync(getEndpoint(), contentType, accept, uploadFileRequest, requestOptions,
             Context.NONE);
     }
 
@@ -1775,7 +1794,7 @@ public Response<BinaryData> uploadFileWithResponse(BinaryData uploadFileRequest,
     public Mono<Response<BinaryData>> deleteFileWithResponseAsync(String fileId, RequestOptions requestOptions) {
         final String accept = "application/json";
         return FluxUtil
-            .withContext(context -> service.deleteFile(OPEN_AI_ENDPOINT, fileId, accept, requestOptions, context));
+            .withContext(context -> service.deleteFile(getEndpoint(), fileId, accept, requestOptions, context));
     }
 
     /**
@@ -1801,7 +1820,7 @@ public Mono<Response<BinaryData>> deleteFileWithResponseAsync(String fileId, Req
     @ServiceMethod(returns = ReturnType.SINGLE)
     public Response<BinaryData> deleteFileWithResponse(String fileId, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.deleteFileSync(OPEN_AI_ENDPOINT, fileId, accept, requestOptions, Context.NONE);
+        return service.deleteFileSync(getEndpoint(), fileId, accept, requestOptions, Context.NONE);
     }
 
     /**
@@ -1833,8 +1852,7 @@ public Response<BinaryData> deleteFileWithResponse(String fileId, RequestOptions
     @ServiceMethod(returns = ReturnType.SINGLE)
     public Mono<Response<BinaryData>> getFileWithResponseAsync(String fileId, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return FluxUtil
-            .withContext(context -> service.getFile(OPEN_AI_ENDPOINT, fileId, accept, requestOptions, context));
+        return FluxUtil.withContext(context -> service.getFile(getEndpoint(), fileId, accept, requestOptions, context));
     }
 
     /**
@@ -1865,7 +1883,7 @@ public Mono<Response<BinaryData>> getFileWithResponseAsync(String fileId, Reques
     @ServiceMethod(returns = ReturnType.SINGLE)
     public Response<BinaryData> getFileWithResponse(String fileId, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.getFileSync(OPEN_AI_ENDPOINT, fileId, accept, requestOptions, Context.NONE);
+        return service.getFileSync(getEndpoint(), fileId, accept, requestOptions, Context.NONE);
     }
 
     /**
@@ -1888,7 +1906,7 @@ public Response<BinaryData> getFileWithResponse(String fileId, RequestOptions re
     public Mono<Response<BinaryData>> getFileContentWithResponseAsync(String fileId, RequestOptions requestOptions) {
         final String accept = "application/json";
         return FluxUtil
-            .withContext(context -> service.getFileContent(OPEN_AI_ENDPOINT, fileId, accept, requestOptions, context));
+            .withContext(context -> service.getFileContent(getEndpoint(), fileId, accept, requestOptions, context));
     }
 
     /**
@@ -1910,7 +1928,7 @@ public Mono<Response<BinaryData>> getFileContentWithResponseAsync(String fileId,
     @ServiceMethod(returns = ReturnType.SINGLE)
     public Response<BinaryData> getFileContentWithResponse(String fileId, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.getFileContentSync(OPEN_AI_ENDPOINT, fileId, accept, requestOptions, Context.NONE);
+        return service.getFileContentSync(getEndpoint(), fileId, accept, requestOptions, Context.NONE);
     }
 
     /**
@@ -1986,7 +2004,7 @@ public Response<BinaryData> getFileContentWithResponse(String fileId, RequestOpt
     @ServiceMethod(returns = ReturnType.SINGLE)
     public Mono<Response<BinaryData>> listBatchesWithResponseAsync(RequestOptions requestOptions) {
         final String accept = "application/json";
-        return FluxUtil.withContext(context -> service.listBatches(OPEN_AI_ENDPOINT, accept, requestOptions, context));
+        return FluxUtil.withContext(context -> service.listBatches(getEndpoint(), accept, requestOptions, context));
     }
 
     /**
@@ -2061,7 +2079,7 @@ public Mono<Response<BinaryData>> listBatchesWithResponseAsync(RequestOptions re
     @ServiceMethod(returns = ReturnType.SINGLE)
     public Response<BinaryData> listBatchesWithResponse(RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.listBatchesSync(OPEN_AI_ENDPOINT, accept, requestOptions, Context.NONE);
+        return service.listBatchesSync(getEndpoint(), accept, requestOptions, Context.NONE);
     }
 
     /**
@@ -2137,7 +2155,7 @@ public Mono<Response<BinaryData>> createBatchWithResponseAsync(BinaryData create
         RequestOptions requestOptions) {
         final String accept = "application/json";
         return FluxUtil.withContext(
-            context -> service.createBatch(OPEN_AI_ENDPOINT, accept, createBatchRequest, requestOptions, context));
+            context -> service.createBatch(getEndpoint(), accept, createBatchRequest, requestOptions, context));
     }
 
     /**
@@ -2211,7 +2229,7 @@ public Mono<Response<BinaryData>> createBatchWithResponseAsync(BinaryData create
     @ServiceMethod(returns = ReturnType.SINGLE)
     public Response<BinaryData> createBatchWithResponse(BinaryData createBatchRequest, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.createBatchSync(OPEN_AI_ENDPOINT, accept, createBatchRequest, requestOptions, Context.NONE);
+        return service.createBatchSync(getEndpoint(), accept, createBatchRequest, requestOptions, Context.NONE);
     }
 
     /**
@@ -2272,7 +2290,7 @@ public Response<BinaryData> createBatchWithResponse(BinaryData createBatchReques
     public Mono<Response<BinaryData>> getBatchWithResponseAsync(String batchId, RequestOptions requestOptions) {
         final String accept = "application/json";
         return FluxUtil
-            .withContext(context -> service.getBatch(OPEN_AI_ENDPOINT, batchId, accept, requestOptions, context));
+            .withContext(context -> service.getBatch(getEndpoint(), batchId, accept, requestOptions, context));
     }
 
     /**
@@ -2331,7 +2349,7 @@ public Mono<Response<BinaryData>> getBatchWithResponseAsync(String batchId, Requ
     @ServiceMethod(returns = ReturnType.SINGLE)
     public Response<BinaryData> getBatchWithResponse(String batchId, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.getBatchSync(OPEN_AI_ENDPOINT, batchId, accept, requestOptions, Context.NONE);
+        return service.getBatchSync(getEndpoint(), batchId, accept, requestOptions, Context.NONE);
     }
 
     /**
@@ -2392,7 +2410,7 @@ public Response<BinaryData> getBatchWithResponse(String batchId, RequestOptions
     public Mono<Response<BinaryData>> cancelBatchWithResponseAsync(String batchId, RequestOptions requestOptions) {
         final String accept = "application/json";
         return FluxUtil
-            .withContext(context -> service.cancelBatch(OPEN_AI_ENDPOINT, batchId, accept, requestOptions, context));
+            .withContext(context -> service.cancelBatch(getEndpoint(), batchId, accept, requestOptions, context));
     }
 
     /**
@@ -2451,7 +2469,7 @@ public Mono<Response<BinaryData>> cancelBatchWithResponseAsync(String batchId, R
     @ServiceMethod(returns = ReturnType.SINGLE)
     public Response<BinaryData> cancelBatchWithResponse(String batchId, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.cancelBatchSync(OPEN_AI_ENDPOINT, batchId, accept, requestOptions, Context.NONE);
+        return service.cancelBatchSync(getEndpoint(), batchId, accept, requestOptions, Context.NONE);
     }
 
     /**
@@ -2516,8 +2534,8 @@ public Mono<Response<BinaryData>> createUploadWithResponseAsync(BinaryData reque
         RequestOptions requestOptions) {
         final String contentType = "application/json";
         final String accept = "application/json";
-        return FluxUtil.withContext(context -> service.createUpload(OPEN_AI_ENDPOINT, contentType, accept, requestBody,
-            requestOptions, context));
+        return FluxUtil.withContext(
+            context -> service.createUpload(getEndpoint(), contentType, accept, requestBody, requestOptions, context));
     }
 
     /**
@@ -2580,8 +2598,7 @@ public Mono<Response<BinaryData>> createUploadWithResponseAsync(BinaryData reque
     public Response<BinaryData> createUploadWithResponse(BinaryData requestBody, RequestOptions requestOptions) {
         final String contentType = "application/json";
         final String accept = "application/json";
-        return service.createUploadSync(OPEN_AI_ENDPOINT, contentType, accept, requestBody, requestOptions,
-            Context.NONE);
+        return service.createUploadSync(getEndpoint(), contentType, accept, requestBody, requestOptions, Context.NONE);
     }
 
     /**
@@ -2617,7 +2634,7 @@ public Mono<Response<BinaryData>> addUploadPartWithResponseAsync(String uploadId
         RequestOptions requestOptions) {
         final String contentType = "multipart/form-data";
         final String accept = "application/json";
-        return FluxUtil.withContext(context -> service.addUploadPart(OPEN_AI_ENDPOINT, contentType, uploadId, accept,
+        return FluxUtil.withContext(context -> service.addUploadPart(getEndpoint(), contentType, uploadId, accept,
             requestBody, requestOptions, context));
     }
 
@@ -2653,7 +2670,7 @@ public Response<BinaryData> addUploadPartWithResponse(String uploadId, BinaryDat
         RequestOptions requestOptions) {
         final String contentType = "multipart/form-data";
         final String accept = "application/json";
-        return service.addUploadPartSync(OPEN_AI_ENDPOINT, contentType, uploadId, accept, requestBody, requestOptions,
+        return service.addUploadPartSync(getEndpoint(), contentType, uploadId, accept, requestBody, requestOptions,
             Context.NONE);
     }
 
@@ -2718,7 +2735,7 @@ public Mono<Response<BinaryData>> completeUploadWithResponseAsync(String uploadI
         RequestOptions requestOptions) {
         final String contentType = "application/json";
         final String accept = "application/json";
-        return FluxUtil.withContext(context -> service.completeUpload(OPEN_AI_ENDPOINT, uploadId, contentType, accept,
+        return FluxUtil.withContext(context -> service.completeUpload(getEndpoint(), uploadId, contentType, accept,
             requestBody, requestOptions, context));
     }
 
@@ -2782,7 +2799,7 @@ public Response<BinaryData> completeUploadWithResponse(String uploadId, BinaryDa
         RequestOptions requestOptions) {
         final String contentType = "application/json";
         final String accept = "application/json";
-        return service.completeUploadSync(OPEN_AI_ENDPOINT, uploadId, contentType, accept, requestBody, requestOptions,
+        return service.completeUploadSync(getEndpoint(), uploadId, contentType, accept, requestBody, requestOptions,
             Context.NONE);
     }
 
@@ -2826,7 +2843,7 @@ public Response<BinaryData> completeUploadWithResponse(String uploadId, BinaryDa
     public Mono<Response<BinaryData>> cancelUploadWithResponseAsync(String uploadId, RequestOptions requestOptions) {
         final String accept = "application/json";
         return FluxUtil
-            .withContext(context -> service.cancelUpload(OPEN_AI_ENDPOINT, uploadId, accept, requestOptions, context));
+            .withContext(context -> service.cancelUpload(getEndpoint(), uploadId, accept, requestOptions, context));
     }
 
     /**
@@ -2867,6 +2884,6 @@ public Mono<Response<BinaryData>> cancelUploadWithResponseAsync(String uploadId,
     @ServiceMethod(returns = ReturnType.SINGLE)
     public Response<BinaryData> cancelUploadWithResponse(String uploadId, RequestOptions requestOptions) {
         final String accept = "application/json";
-        return service.cancelUploadSync(OPEN_AI_ENDPOINT, uploadId, accept, requestOptions, Context.NONE);
+        return service.cancelUploadSync(getEndpoint(), uploadId, accept, requestOptions, Context.NONE);
     }
 }
diff --git a/sdk/openai/azure-ai-openai/src/test/java/com/azure/ai/openai/OpenAIClientBuilderTest.java b/sdk/openai/azure-ai-openai/src/test/java/com/azure/ai/openai/OpenAIClientBuilderTest.java
new file mode 100644
index 000000000000..b5d0ee597c8b
--- /dev/null
+++ b/sdk/openai/azure-ai-openai/src/test/java/com/azure/ai/openai/OpenAIClientBuilderTest.java
@@ -0,0 +1,52 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+package com.azure.ai.openai;
+
+import static com.azure.ai.openai.implementation.NonAzureOpenAIClientImpl.OPEN_AI_ENDPOINT_PATTERN;
+import java.lang.reflect.Field;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import org.junit.jupiter.api.Test;
+import static com.azure.ai.openai.implementation.NonAzureOpenAIClientImpl.OPEN_AI_ENDPOINT;
+
+public class OpenAIClientBuilderTest {
+    @Test
+    public void testEndpointPattern() {
+        assertTrue(OPEN_AI_ENDPOINT_PATTERN.matcher(OPEN_AI_ENDPOINT).matches());
+        assertTrue(OPEN_AI_ENDPOINT_PATTERN.matcher("https://eu.api.openai.com/v1").matches());
+        assertTrue(OPEN_AI_ENDPOINT_PATTERN.matcher("https://asdf.api.openai.com/v1").matches());
+        assertFalse(OPEN_AI_ENDPOINT_PATTERN.matcher("http://api.openai.com/v1").matches());
+        assertFalse(OPEN_AI_ENDPOINT_PATTERN.matcher("https://api.openai.com/").matches());
+        assertFalse(OPEN_AI_ENDPOINT_PATTERN.matcher("https://dead.beef.api.openai.com/v1").matches());
+        assertFalse(OPEN_AI_ENDPOINT_PATTERN.matcher("https://api.openai.com.org/v1").matches());
+        assertFalse(OPEN_AI_ENDPOINT_PATTERN.matcher("https://api.openai.com/v2").matches());
+    }
+
+    @Test
+    public void testInnerImplBasedOnEndpoint() throws NoSuchFieldException, IllegalAccessException {
+        Field azureClient = OpenAIClient.class.getDeclaredField("serviceClient");
+        azureClient.setAccessible(true);
+        Field nonAzureClient = OpenAIClient.class.getDeclaredField("openAIServiceClient");
+        nonAzureClient.setAccessible(true);
+
+        OpenAIClient nullEndpointClient = new OpenAIClientBuilder().buildClient();
+        assertNull(azureClient.get(nullEndpointClient));
+        assertNotNull(nonAzureClient.get(nullEndpointClient));
+
+        OpenAIClient customEndpointClient
+            = new OpenAIClientBuilder().endpoint("https://my.custom.domain/").buildClient();
+        assertNotNull(azureClient.get(customEndpointClient));
+        assertNull(nonAzureClient.get(customEndpointClient));
+
+        OpenAIClient defaultEndpointClient = new OpenAIClientBuilder().endpoint(OPEN_AI_ENDPOINT).buildClient();
+        assertNull(azureClient.get(defaultEndpointClient));
+        assertNotNull(nonAzureClient.get(defaultEndpointClient));
+
+        OpenAIClient euEndpointClient
+            = new OpenAIClientBuilder().endpoint("https://eu.api.openai.com/v1").buildClient();
+        assertNull(azureClient.get(euEndpointClient));
+        assertNotNull(nonAzureClient.get(euEndpointClient));
+    }
+}