Azure OpenAI
Learn how to use the Azure OpenAI provider for the AI SDK.
The Azure OpenAI provider contains language model support for the Azure OpenAI chat API.
Setup
The Azure OpenAI provider is available in the @ai-sdk/azure module. You can install it with
$ pnpm add @ai-sdk/azure
$ npm install @ai-sdk/azure
$ yarn add @ai-sdk/azure
$ bun add @ai-sdk/azure
Provider Instance
You can import the default provider instance azure from @ai-sdk/azure:
If you need a customized setup, you can import createAzure from @ai-sdk/azure and create a provider instance with your settings:
You can also use a complete Microsoft Foundry OpenAI v1 base URL:
For Microsoft Entra ID authentication, you can provide a token provider.
Install @azure/identity separately if you want to use its credential helpers:
You can use the following optional settings to customize the OpenAI provider instance:
-
resourceName string
Azure resource name. It defaults to the
AZURE_RESOURCE_NAMEenvironment variable.The resource name is used in the assembled URL:
https://{resourceName}.openai.azure.com/openai/v1{path}. It must be a single DNS label (letters, digits, and hyphens). You can usebaseURLinstead to specify the URL prefix. -
apiKey string
API key that is being sent using the
api-keyheader. It defaults to theAZURE_API_KEYenvironment variable. -
tokenProvider () => Promise<string>
Microsoft Entra ID token provider that returns an access token to be sent using the
Authorizationheader. When provided, this is used instead ofapiKey. -
apiVersion string
Sets a custom api version. Defaults to
v1. This setting is applied when the provider constructs the v1 path or uses deployment-based URLs. Complete v1 base URLs are used as-is. -
baseURL string
Use a different URL prefix for API calls, e.g. to use proxy servers.
Either this or
resourceNamecan be used. When a baseURL is provided, the resourceName is ignored.For Azure-hosted URLs ending in
.openai.azure.com,.services.ai.azure.com, or.cognitiveservices.azure.com, you can pass either an unversioned OpenAI prefix such ashttps://your-resource.services.ai.azure.com/openaior a complete v1 base URL such ashttps://your-resource.services.ai.azure.com/openai/v1. The provider appends/v1and the configuredapi-versionto unversioned resource URLs. Complete v1 URLs are used as-is.Complete Microsoft Foundry project v1 URLs, such as
https://your-resource.services.ai.azure.com/api/projects/your-project/openai/v1, are also used as-is. If/v1is omitted from a Foundry project URL, the provider appends it without adding anapi-versionquery parameter.With a non-Azure custom gateway baseURL, the resolved URL is
{baseURL}{path}; the SDK does not append/v1or anapi-versionquery parameter in this mode. -
headers Record<string,string>
Custom headers to include in the requests.
-
fetch (input: RequestInfo, init?: RequestInit) => Promise<Response>
Custom fetch implementation. Defaults to the global
fetchfunction. You can use it as a middleware to intercept requests, or to provide a custom fetch implementation for e.g. testing. -
useDeploymentBasedUrls boolean
Use deployment-based URLs for API calls. Set to
trueto use the legacy deployment format:{baseURL}/deployments/{deploymentId}{path}?api-version={apiVersion}instead of{baseURL}/v1{path}?api-version={apiVersion}. Defaults tofalse.This option is useful for compatibility with certain Azure OpenAI models or deployments that require the legacy endpoint format.
-
speechBaseURL string
URL prefix for Azure Speech requests (MAI-Transcribe transcription and MAI-Voice speech generation), for example a regional endpoint such as
https://eastus.api.cognitive.microsoft.com. Defaults tohttps://{resourceName}.cognitiveservices.azure.com. Speech requests do not usebaseURLorapiVersion. -
maiBaseURL string
URL prefix for MAI requests (MAI-Image and MAI-Transcribe-2-Streaming). Defaults to
https://{resourceName}.services.ai.azure.com/mai/v1. -
webSocket WebSocketConstructor
Custom WebSocket implementation for MAI streaming transcription, for example the
WebSocketexport of thewspackage in Node.js. With a custom implementation the API key is sent in theapi-keyheader; with the nativeWebSocketit is sent as theapi-keyquery parameter. Microsoft Entra ID (tokenProvider) authentication requires a custom implementation; without one, streaming fails with anInvalidArgumentErrorbefore connecting.
Language Models
The Azure OpenAI provider instance is a function that you can invoke to create a language model:
You need to pass your deployment name as the first argument.
Reasoning Models
Azure exposes the thinking of DeepSeek-R1 in the generated text using the <think> tag.
You can use the extractReasoningMiddleware to extract this reasoning and expose it as a reasoning property on the result:
You can then use that enhanced model in functions like generateText and streamText.
The Azure provider calls the Responses API by default (unless you specify e.g.
azure.chat).
Example
You can use OpenAI language models to generate text with the generateText function:
OpenAI language models can also be used in the streamText function
and support structured data generation with Output
(see AI SDK Core).
Azure OpenAI sends larger chunks than OpenAI. This can lead to the perception that the response is slower. See Troubleshooting: Azure OpenAI Slow To Stream
Provider Options
When using OpenAI language models on Azure, you can configure provider-specific options using providerOptions.openai. More information on available configuration options are on the OpenAI provider page.
Chat Models
The URL for calling Azure chat models will be constructed as follows:
https://RESOURCE_NAME.openai.azure.com/openai/v1/chat/completions?api-version=v1
You can create models that call the Azure OpenAI chat completions API using the .chat() factory method:
Azure OpenAI chat models support also some model specific settings that are not part of the standard call settings. You can pass them as an options argument:
The following optional provider options are available for OpenAI chat models:
-
logitBias Record<number, number>
Modifies the likelihood of specified tokens appearing in the completion.
Accepts a JSON object that maps tokens (specified by their token ID in the GPT tokenizer) to an associated bias value from -100 to 100. You can use this tokenizer tool to convert text to token IDs. Mathematically, the bias is added to the logits generated by the model prior to sampling. The exact effect will vary per model, but values between -1 and 1 should decrease or increase likelihood of selection; values like -100 or 100 should result in a ban or exclusive selection of the relevant token.
As an example, you can pass
{"50256": -100}to prevent the token from being generated. -
logprobs boolean | number
Return the log probabilities of the tokens. Including logprobs will increase the response size and can slow down response times. However, it can be useful to better understand how the model is behaving.
Setting to true will return the log probabilities of the tokens that were generated.
Setting to a number will return the log probabilities of the top n tokens that were generated.
-
parallelToolCalls boolean
Whether to enable parallel function calling during tool use. Default to true.
-
user string
A unique identifier representing your end-user, which can help OpenAI to monitor and detect abuse. Learn more.
DeepSeek Chat Models
You can create Azure-hosted DeepSeek chat models using the .deepseek() factory method:
Use this factory for Azure DeepSeek models that support DeepSeek's chat
reasoning fields, such as deepseek-v4-pro and deepseek-v4-flash. The
factory maps top-level reasoning to DeepSeek reasoning_effort request
settings, and parses streamed reasoning_content as AI SDK reasoning parts.
Responses Models
Azure OpenAI uses responses API as default with the azure(deploymentName) factory method.
Further configuration can be done using OpenAI provider options.
You can validate the provider options using the OpenAILanguageModelResponsesOptions type.
In the Responses API, use azure as the provider name in providerOptions
instead of openai. The openai key is still supported for providerOptions
input.
The following provider options are available:
-
parallelToolCalls boolean Whether to use parallel tool calls. Defaults to
true. -
store boolean Whether to store the generation. Defaults to
true. -
metadata Record<string, string> Additional metadata to store with the generation.
-
previousResponseId string The ID of the previous response. You can use it to continue a conversation. Defaults to
undefined. -
instructions string Instructions for the model. They can be used to change the system or developer message when continuing a conversation using the
previousResponseIdoption. Defaults toundefined. -
user string A unique identifier representing your end-user, which can help OpenAI to monitor and detect abuse. Defaults to
undefined. -
reasoningEffort 'low' | 'medium' | 'high' Reasoning effort for reasoning models. Defaults to
medium. If you useproviderOptionsto set thereasoningEffortoption, this model setting will be ignored. -
strictJsonSchema boolean Whether to use strict JSON schema validation. Defaults to
false.
The Azure OpenAI provider also returns provider-specific metadata:
For Responses models (azure(deploymentName)), you can type this metadata using AzureResponsesProviderMetadata:
The following Azure-specific metadata may be returned:
- responseId string | null | undefined The ID of the response. Can be used to continue a conversation.
- logprobs (optional) Log probabilities of output tokens (when enabled).
- serviceTier (optional) Service tier information returned by the API.
The providerMetadata is only returned with the default responses API, and is not supported when using 'azure.chat' or 'azure.completion'
Changing Reasoning Effort Mid-Conversation
Azure Responses models support message-level reasoning effort updates through
providerOptions.azure.reasoningEffortUpdate. The openai namespace is also
accepted when the message has no azure options. Use the
OpenAIResponsesSystemMessageOptions type exported from @ai-sdk/azure to
validate these options:
Keep the request-level reasoning unchanged throughout the conversation and
retain earlier effort updates when resending message history. These updates
also work with streamText. See the OpenAI reasoning effort
guide
for continuation, compaction, and configuration restrictions.
The SDK infers support for effort updates from the deployment name passed to
azure.responses(). The name must identify a supported GPT-6-or-later model
family, such as gpt-6-astra. A custom name such as production is not
recognized, even when the underlying deployment runs GPT-6. In that case,
message-level updates throw, and request-level updates are omitted with a
warning. Setting forceReasoning: true does not override this capability
check.
Web Search Tool
The Azure OpenAI responses API supports web search through the azure.tools.webSearch tool.
The web search tool supports the following configuration options:
- externalWebAccess boolean - Whether to use external web access for fetching live content. Defaults to
true. - searchContextSize 'low' | 'medium' | 'high' - Controls the amount of context used for the search. Higher values provide more comprehensive results but may have higher latency and cost.
- userLocation - Optional location information to provide geographically relevant results. Includes
type(always'approximate'),country,city,region, andtimezone. - filters - Optional filter configuration to restrict search results.
- allowedDomains string[] - Up to 100 allowed domains for the search.
- blockedDomains string[] - Up to 100 blocked domains for the search.
Omit the HTTP or HTTPS prefix from domain filters. Subdomains of configured domains are automatically included or excluded.
For detailed information on configuration options see the Azure OpenAI Web Search Tool documentation.
On Microsoft Foundry environment , Live internet access is not supported. The
parameter externalWebAccess if passed will be ignored.
File Search Tool
The Azure OpenAI provider supports file search through the azure.tools.fileSearch tool.
You can force the use of the file search tool by setting the toolChoice parameter to { type: 'tool', toolName: 'file_search' }.
The tool must be named file_search when using Azure OpenAI's file search
functionality. This name is required by Azure OpenAI's API specification and
cannot be customized.
The 'file_search' tool is only supported with the default responses API, and is not supported when using 'azure.chat' or 'azure.completion'
Image Generation Tool
Azure OpenAI's Responses API supports multi-modal image generation as a provider-defined tool.
Availability is restricted to specific models (for example, gpt-5 variants).
The tool must be named image_generation when using Azure OpenAI's image
generation functionality. This name is required by Azure OpenAI's API
specification and cannot be customized.
The 'image_generation' tool is only supported with the default responses API, and is not supported when using 'azure.chat' or 'azure.completion'
To use image_generation, you must first create an image generation model. You
must add a deployment specification to the header
x-ms-oai-image-generation-deployment. Please note that the Responses API
model and the image generation model must be in the same resource.
When you set store: false, then previously generated images will not be
accessible by the model. We recommend using the image generation tool without
setting store: false.
Code Interpreter Tool
The Azure OpenAI provider supports the code interpreter tool through the azure.tools.codeInterpreter tool. This allows models to write and execute Python code.
The code interpreter tool can be configured with:
- container: Either a container ID string or an object with
fileIdsto specify uploaded files that should be available to the code interpreter
The tool must be named code_interpreter when using Azure OpenAI's code
interpreter functionality. This name is required by Azure OpenAI's API
specification and cannot be customized.
The 'code_interpreter' tool is only supported with the default responses API, and is not supported when using 'azure.chat' or 'azure.completion'
When working with files generated by the Code Interpreter, reference
information can be obtained from both annotations in Text
Parts and providerMetadata in
Source Document Parts.
PDF support
The Azure OpenAI provider supports reading PDF files.
You can pass PDF files as part of the message content using the file type:
The model will have access to the contents of the PDF file and
respond to questions about it.
The PDF file should be passed using the data field,
and the mediaType should be set to 'application/pdf'.
Reading PDF files are only supported with the default responses API, and is not supported when using 'azure.chat' or 'azure.completion'
Typed providerMetadata in Text Parts
When using the Azure OpenAI Responses API, the SDK attaches Azure OpenAI-specific metadata to output parts via providerMetadata.
This metadata can be used on the client side for tasks such as rendering citations or downloading files generated by the Code Interpreter. To enable type-safe handling of this metadata, the AI SDK exports dedicated TypeScript types.
For text parts, when part.type === 'text', the providerMetadata is provided in the form of AzureResponsesTextProviderMetadata.
This metadata includes the following fields:
-
itemId
The ID of the output item in the Responses API. -
annotations(optional) An array of annotation objects generated by the model. If no annotations are present, this property itself may be omitted (undefined).Each element in
annotationsis a discriminated union with a requiredtypefield. Supported types include, for example:url_citationfile_citationcontainer_file_citationfile_path
These annotations directly correspond to the annotation objects defined by the Responses API and can be used for inline reference rendering or output analysis. For details, see the official OpenAI documentation: Responses API – output text annotations.
When implementing file downloads for files generated by the Code Interpreter,
the container_id and file_id available in providerMetadata can be used
to retrieve the file content. For details, see the Retrieve container file
content
API.
Typed providerMetadata in Reasoning Parts
When using the Azure OpenAI Responses API, reasoning output parts can include provider metadata.
To handle this metadata in a type-safe way, use AzureResponsesReasoningProviderMetadata.
For reasoning parts, when part.type === 'reasoning', the providerMetadata is provided in the form of AzureResponsesReasoningProviderMetadata.
This metadata includes the following fields:
itemId
The ID of the reasoning item in the Responses API.reasoningEncryptedContent(optional)
Encrypted reasoning content (only returned when requested viainclude: ['reasoning.encrypted_content']).
Typed providerMetadata in Source Document Parts
For source document parts, when part.type === 'source' and sourceType === 'document', the providerMetadata is provided as AzureResponsesSourceDocumentProviderMetadata.
This metadata is also a discriminated union with a required type field. Supported types include:
file_citationcontainer_file_citationfile_path
Each type includes the identifiers required to work with the referenced resource, such as fileId and containerId.
Annotations in text parts follow the OpenAI Responses API specification and
therefore use snake_case properties (e.g. file_id, container_id). In
contrast, providerMetadata for source document parts is normalized by the
SDK to camelCase (e.g. fileId, containerId). Fields that depend on the
original text content, such as start_index and end_index, are omitted, as
are fields like filename that are directly available on the source object.
Completion Models
You can create models that call the completions API using the .completion() factory method.
The first argument is the model id.
Currently only gpt-35-turbo-instruct is supported.
OpenAI completion models support also some model specific settings that are not part of the standard call settings. You can pass them as an options argument:
The following optional provider options are available for Azure OpenAI completion models:
-
echo: boolean
Echo back the prompt in addition to the completion.
-
logitBias Record<number, number>
Modifies the likelihood of specified tokens appearing in the completion.
Accepts a JSON object that maps tokens (specified by their token ID in the GPT tokenizer) to an associated bias value from -100 to 100. You can use this tokenizer tool to convert text to token IDs. Mathematically, the bias is added to the logits generated by the model prior to sampling. The exact effect will vary per model, but values between -1 and 1 should decrease or increase likelihood of selection; values like -100 or 100 should result in a ban or exclusive selection of the relevant token.
As an example, you can pass
{"50256": -100}to prevent the <|endoftext|> token from being generated. -
logprobs boolean | number
Return the log probabilities of the tokens. Including logprobs will increase the response size and can slow down response times. However, it can be useful to better understand how the model is behaving.
Setting to true will return the log probabilities of the tokens that were generated.
Setting to a number will return the log probabilities of the top n tokens that were generated.
-
suffix string
The suffix that comes after a completion of inserted text.
-
user string
A unique identifier representing your end-user, which can help OpenAI to monitor and detect abuse. Learn more.
Embedding Models
You can create models that call the Azure OpenAI embeddings API
using the .embedding() factory method.
Azure OpenAI embedding models support several additional settings. You can pass them as an options argument:
The following optional provider options are available for Azure OpenAI embedding models:
-
dimensions: number
The number of dimensions the resulting output embeddings should have. Only supported in text-embedding-3 and later models.
-
user string
A unique identifier representing your end-user, which can help OpenAI to monitor and detect abuse. Learn more.
Image Models
You can create models that call the Azure OpenAI image generation API using the .image() factory method. The first argument is your deployment name.
MAI-Image models use the MAI image API instead.
Azure OpenAI image models support several additional settings. You can pass them as providerOptions.openai when generating the image:
Example
You can use Azure OpenAI image models to generate images with the generateImage function:
Model Capabilities
Azure OpenAI supports DALL-E 2 and DALL-E 3 models through deployments. The capabilities depend on which model version your deployment is using:
| Model Version | Sizes |
|---|---|
| DALL-E 3 | 1024x1024, 1792x1024, 1024x1792 |
| DALL-E 2 | 256x256, 512x512, 1024x1024 |
Azure deployment names are user-defined and do not identify the backing model.
Consequently, supportsFileInputs and supportsMaskInputs are undefined
(unknown) for Azure image model instances. If your application knows the
capabilities of a deployment, you can advertise them with the
overrideSupportsFileInputs and overrideSupportsMaskInputs options of
wrapImageModel.
DALL-E models do not support the aspectRatio parameter. Use the size
parameter instead.
When creating your Azure OpenAI deployment, make sure to set the DALL-E model version you want to use.
MAI-Image
MAI-Image models (MAI-Image-2.6, MAI-Image-2.6-Flash, MAI-Image-2.5,
MAI-Image-2.5-Flash, MAI-Image-2.5-Pro) use the MAI image API at
https://{resourceName}.services.ai.azure.com/mai/v1 (override with
maiBaseURL). Deployments named after the model are detected automatically,
case-insensitively. For other deployment names, set
providerOptions.azure.api to 'mai'.
Pass reference images to edit or combine them (up to five JPEG or PNG images). Masks are not supported.
Each request returns one PNG image; generateImage sends one request per image.
size is sent as width and height. Each side must be at least 768 pixels,
and the total pixel count at most 2,359,296 for MAI-Image-2.6 models and
1,048,576 for MAI-Image-2.5 models. Without size, aspectRatio is mapped to
dimensions of about one megapixel; without either, the model returns 1024x1024.
seed is not supported. Token usage is returned in usage, with the input
text and image token split in providerMetadata.azure.images.
The following provider options are available:
-
api 'mai' | 'openai'
API to use. Defaults to
'mai'for MAI-Image models,'openai'otherwise. -
autoAspectRatio boolean
Let the model choose the output aspect ratio from the prompt and reference images. MAI-Image-2.6 models only.
-
webGrounding boolean
Ground generation in Bing web search results. MAI-Image-2.6 models only.
Transcription Models
You can create models that call the Azure OpenAI or Azure Speech transcription API using the .transcription() factory method.
The first argument is the model id e.g. whisper-1.
MAI-Transcribe
MAI-Transcribe models are multilingual speech-to-text models from Microsoft AI, served through Azure. The following model IDs use the Azure Speech API. They are matched case-insensitively and sent to Azure under their Azure model names:
| Model ID | Azure model | Notes |
|---|---|---|
mai-transcribe-2 | MAI-Transcribe-2 | Supports every option below. |
mai-transcribe-1.5 | MAI-Transcribe-1.5 | Supports locales and phraseList. |
mai-transcribe-2-streaming uses the MAI realtime API; see
MAI-Transcribe-2-Streaming. All other IDs use the
OpenAI API by default, including custom deployment names.
MAI-Transcribe models require a Microsoft Foundry (Speech) resource in a region where they are available:
centralindia, eastus, northeurope, southeastasia, westus, or westus2
(see Speech service regions).
Resources in other regions reject the request.
Set AZURE_RESOURCE_NAME and AZURE_API_KEY to that resource's name and key,
or pass resourceName and apiKey to createAzure. tokenProvider, custom headers,
and custom fetch are also supported. Keys are sent as Ocp-Apim-Subscription-Key.
Speech requests use https://{resourceName}.cognitiveservices.azure.com/speechtotext/transcriptions:transcribe
with API version 2025-10-15. Use speechBaseURL to supply a different Speech URL prefix
(without /speechtotext/transcriptions:transcribe), for example a regional endpoint:
Speech requests do not use baseURL, apiVersion, or useDeploymentBasedUrls;
those settings only apply to Azure OpenAI models.
The following options are available through providerOptions.azure:
-
api 'openai' | 'speech' Overrides model-based API selection for this request. Set
openaifor an OpenAI deployment named after one of the model IDs above, orspeechto send another model ID to Speech. Other Speech model IDs are sent unchanged. -
timestamps 'word' | 'segment' | 'none' Timing granularity. For MAI-Transcribe-2 the AI SDK defaults to
segmentso that results include timed segments (Azure's own default isnone).segmentreturns one segment per sentence or speaker turn,wordadditionally returns word timing in provider metadata, andnonereturns a single segment that spans the whole audio. MAI-Transcribe-1.5 only supportsnone, so the AI SDK does not send a default for it. -
transcribeStyle 'verbatim' | 'clean'
verbatimkeeps fillers and false starts,cleanremoves them. Defaults toverbatim.cleanrequires MAI-Transcribe-2. -
locales string[] Exactly one language code, such as
['en']. This is a strong hint; omit it for automatic language detection and code switching. -
diarization object Set
enabledtotrueto identify speakers. Speaker IDs are returned in provider metadata. Requires MAI-Transcribe-2.maxSpeakersis not supported. -
phraseList object Set
phrasesto a list of names and domain terms to bias recognition toward them.
Explicit api takes precedence over the model ID. Existing OpenAI transcription
options remain under providerOptions.openai. Speech-only Azure options produce
warnings when used with the OpenAI API. Unknown providerOptions.azure keys
(for example diarization.maxSpeakers) are rejected before the request is sent.
Options that a model does not support, such as timestamps: 'word' with
MAI-Transcribe-1.5, are sent unchanged, and Azure rejects the request with an
error that names the option.
Results include transcript text, timed segments, duration, and an ISO-639-1
language code when the reported phrase locales identify one language. Mixed-language
results, and languages without an ISO-639-1 code such as Filipino (fil) or
Cantonese (yue), leave language undefined. Speaker IDs, exact locales, and word
timing are preserved in providerMetadata.azure.phrases; use the exported
AzureTranscriptionProviderMetadata type to access them. Phrase timing is in
milliseconds in metadata and seconds in normalized segments.
MAI-Transcribe models are file transcription models: they accept WAV, MP3, or FLAC files shorter than 2 hours and smaller than 250 MB, and do not support streaming transcription; use MAI-Transcribe-2-Streaming to stream. The models are in public preview. See Azure's MAI-Transcribe guide for supported languages and diarization limits.
AI Gateway forwards these provider options, including azure.api.
MAI-Transcribe-2-Streaming
MAI-Transcribe-2-Streaming is a low-latency streaming speech-to-text model from Microsoft AI.
azure.transcription('mai-transcribe-2-streaming') streams audio to the MAI realtime API
(wss://{resourceName}.services.ai.azure.com/mai/v1/realtime) with
experimental_streamTranscribe.
The model ID is sent to Azure as the Foundry deployment name, so deploy the model
as mai-transcribe-2-streaming, or set api: 'mai' for other deployment names.
The model requires a Microsoft Foundry resource with a MAI-Transcribe-2-Streaming
deployment in a supported region, such as centralus.
Input audio must be 16-bit mono PCM (audio/pcm) at 16000 or 24000 Hz; the default is 24000 Hz.
The stream emits transcript-delta parts for finalized text and transcript-partial
parts for the provisional text that follows the latest delta. MAI does not detect
pauses on the server, so the stream commits once when the input audio ends and then
emits a transcript-final part and the finished transcript. durationInSeconds is
computed from the streamed audio.
The following options are available through providerOptions.azure:
-
api 'openai' | 'speech' | 'mai' Set
maito stream with a deployment that has a different name. -
language string Language hint such as
en. Omit for automatic language detection.
File transcription options such as timestamps produce warnings when streaming.
MAI-Transcribe-2-Streaming does not support file transcription.
OpenAI transcription
If you encounter a "DeploymentNotFound" error with transcription models, try enabling deployment-based URLs:
This uses the legacy endpoint format which may be required for certain Azure OpenAI deployments.
When using useDeploymentBasedUrls, the default api-version is not valid. You must set it to 2025-04-01-preview or an earlier value.
You can also pass additional provider-specific options using the providerOptions argument. For example, supplying the input language in ISO-639-1 (e.g. en) format will improve accuracy and latency.
The following provider options are available:
-
timestampGranularities string[] The granularity of the timestamps in the transcription. Defaults to
['segment']. Possible values are['word'],['segment'], and['word', 'segment']. Note: There is no additional latency for segment timestamps, but generating word timestamps incurs additional latency. -
language string The language of the input audio. Supplying the input language in ISO-639-1 format (e.g. 'en') will improve accuracy and latency. Optional.
-
prompt string An optional text to guide the model's style or continue a previous audio segment. The prompt should match the audio language. Optional.
-
temperature number The sampling temperature, between 0 and 1. Higher values like 0.8 will make the output more random, while lower values like 0.2 will make it more focused and deterministic. If set to 0, the model will use log probability to automatically increase the temperature until certain thresholds are hit. Defaults to 0. Optional.
-
include string[] Additional information to include in the transcription response.
Model Capabilities
| Model | Transcription | Duration | Segments | Language |
|---|---|---|---|---|
whisper-1 | ||||
gpt-4o-mini-transcribe | ||||
gpt-4o-transcribe | ||||
mai-transcribe-2 | ||||
mai-transcribe-1.5 | ||||
mai-transcribe-2-streaming | (streaming) |
Speech Models
You can create models that call the Azure OpenAI speech API or Azure Speech text to speech using the .speech() factory method.
The first argument is your deployment name for the text-to-speech model (e.g., tts-1),
or a MAI-Voice model ID.
Example
You can also pass additional provider-specific options using the providerOptions argument:
The following provider options are available:
-
instructions string Control the voice of your generated audio with additional instructions e.g. "Speak in a slow and steady tone". Does not work with
tts-1ortts-1-hd. Optional. -
speed number The speed of the generated audio. Select a value from 0.25 to 4.0. Defaults to 1.0. Optional.
Model Capabilities
Azure OpenAI supports TTS models through deployments. The capabilities depend on which model version your deployment is using:
| Model Version | Instructions |
|---|---|
tts-1 | |
tts-1-hd | |
gpt-4o-mini-tts |
MAI-Voice
MAI-Voice models are multilingual text-to-speech models from Microsoft AI, served through Azure. The following model IDs use the Azure Speech API:
| Model ID | Notes |
|---|---|
mai-voice-2.1-flash | Low latency, for voice agents and assistants. |
mai-voice-2.1 | Highest fidelity, for long-form narration. |
mai-voice-2-flash | Low latency, for voice agents and assistants. |
mai-voice-2 | Highest fidelity, for long-form narration. |
All other IDs use the OpenAI API by default, including custom deployment names.
MAI-Voice models require a Microsoft Foundry (Speech) resource in a region where they are available
(see Speech service regions).
They use the same settings as MAI-Transcribe: resourceName (or AZURE_RESOURCE_NAME),
apiKey (or AZURE_API_KEY), tokenProvider, and speechBaseURL.
- voice is a prebuilt voice ID that includes its locale, such as
en-US-Harper(the default),de-DE-Mia, ores-MX-Valeria. The voice locale selects the language. Full Azure voice names such ases-MX-Valeria:MAI-Voice-2are also accepted. Available voices vary by model; see Azure's MAI-Voice guide. - language picks a default voice when
voiceis not set (see the table below). Other languages andautouseen-US-Harperwith a warning. Whenvoiceis set, its locale selects the language, and a conflictinglanguageproduces a warning. - outputFormat accepts
mp3(default, 24 kHz),wav,pcm(headerless 24 kHz, 16-bit, mono),opus(Ogg), or any AzureX-Microsoft-OutputFormatvalue such asaudio-48khz-192kbitrate-mono-mp3. Other values fall back tomp3with a warning. Azure labels raw formats such aspcmasaudio/basic. - speed is a rate multiplier, for example
0.5for half speed or2for double speed. instructionsis not supported and produces a warning.
| Language | Default voice | Language | Default voice |
|---|---|---|---|
de | de-DE-Mia | nl | nl-NL-Fleur |
en | en-US-Harper | pt | pt-BR-Luana |
es | es-MX-Valeria | ro | ro-RO-Elena |
fr | fr-FR-Soleil | ru | ru-RU-Masha |
hi | hi-IN-Kavya | th | th-TH-Krit |
hu | hu-HU-Lilla | tr | tr-TR-Elif |
it | it-IT-Rosa | zh | zh-CN-Mei |
ko | ko-KR-Haena |
The following options are available through providerOptions.azure:
-
api 'openai' | 'speech' Overrides model-based API selection for this request. Set
openaifor an OpenAI deployment named after one of the model IDs above, orspeechto send another model ID to Speech. -
style string Speaking style, such as
excitedorwhispering. Supported styles vary by voice and model. -
styleDegree number Style intensity from 0.01 to 2. Azure defaults to 1. Requires
style.
Text is always spoken as plain text; SSML input is not supported.
The models are in public preview. AI Gateway forwards these provider options, including azure.api.