Training Sets - Upload Data

Service:: Azure AI Services

API Version:: 2026-01-01

Uploads data to the specified training set.

POST {endpoint}/customvoice/trainingsets/{id}:upload?api-version=2026-01-01

URI Parameters

Name	In	Required	Type	Description
endpoint	path	True	string (uri)	Supported Cognitive Services endpoints (protocol and hostname, for example: https://eastus.api.cognitive.microsoft.com).
id	path	True	string minLength: 3 maxLength: 64 pattern: ^[a-zA-Z0-9][a-zA-Z0-9._-]{1,62}[a-zA-Z0-9]$	The ID of the resource.
api-version	query	True	string minLength: 1	The API version to use for this operation.

Request Header

Name	Required	Type	Description
Operation-Id		string minLength: 3 maxLength: 64 pattern: ^[a-zA-Z0-9][a-zA-Z0-9._-]{1,62}[a-zA-Z0-9]$	ID of the status monitor for the operation. If the Operation-Id header matches an existing operation and the request is not identical to the prior request, it will fail with a 400 Bad Request.

Request Body

Name	Required	Type	Description
audios	True	AzureBlobContentSource	Azure Blob Storage content. With the examples below, it represents files `https://contoso.blob.core.windows.net/voicecontainer/jessica/*.wav`
kind	True	DatasetKind	Dataset kind
description		string	Optional description of this dataset.
displayName		string	The name of this dataset.
processAs		DatasetProcessAs	Dataset processing method. If not specified, the default processing method will be used.
scripts		AzureBlobContentSource	Azure Blob Storage content. With the examples below, it represents files `https://contoso.blob.core.windows.net/voicecontainer/jessica/*.wav`

Responses

Name	Type	Description
202 Accepted		The request has been accepted for processing, but processing has not yet completed. Headers Operation-Id: string Operation-Location: string
Other Status Codes	Azure.Core.Foundations.ErrorResponse	An unexpected error response. Headers x-ms-error-code: string

Name

Type

Description

202 Accepted

The request has been accepted for processing, but processing has not yet completed.

Headers

Operation-Id: string
Operation-Location: string

Other Status Codes

Azure.Core.Foundations.ErrorResponse

An unexpected error response.

Headers

x-ms-error-code: string

Security

Ocp-Apim-Subscription-Key

Type: apiKey
In: header

OAuth2Auth

Type: oauth2
Flow: implicit
Authorization URL: https://login.microsoftonline.com/common/oauth2/authorize

Scopes

Name	Description
https://cognitiveservices.azure.com/.default

Examples

Upload data to a training set

Sample request

HTTP

POST {endpoint}/customvoice/trainingsets/d6916a55-2cbc-4ed4-bd19-739e9a13b0ab:upload?api-version=2026-01-01


{
  "audios": {
    "containerUrl": "https://contoso.blob.core.windows.net/voicecontainer?mySasToken",
    "prefix": "jessica300/",
    "extensions": [
      ".wav"
    ]
  },
  "kind": "AudioAndScript",
  "processAs": "Segmented",
  "scripts": {
    "containerUrl": "https://contoso.blob.core.windows.net/voicecontainer?mySasToken",
    "prefix": "jessica300/",
    "extensions": [
      ".txt"
    ]
  }
}

Sample response

Status code:: 202

Operation-Id: 284b7e37-f42d-4054-8fa9-08523c3de345
Operation-Location: https://eastus.api.cognitive.microsoft.com/customvoice/operations/284b7e37-f42d-4054-8fa9-08523c3de345?api-version=2026-01-01

Definitions

Name	Description
Azure.Core.Foundations.Error	The error object.
Azure.Core.Foundations.ErrorResponse	A response containing error details.
Azure.Core.Foundations.InnerError	An object containing more specific information about the error. As per Azure REST API guidelines - https://aka.ms/AzureRestApiGuidelines#handling-errors.
AzureBlobContentSource	Azure Blob Storage content. With the examples below, it represents files `https://contoso.blob.core.windows.net/voicecontainer/jessica/*.wav`
Dataset	Dataset object
DatasetKind	Dataset kind
DatasetProcessAs	Dataset processing method. If not specified, the default processing method will be used.

Azure.Core.Foundations.Error

Object

The error object.

Name	Type	Description
code	string	One of a server-defined set of error codes.
details	Azure.Core.Foundations.Error[]	An array of details about specific errors that led to this reported error.
innererror	Azure.Core.Foundations.InnerError	An object containing more specific information than the current object about the error.
message	string	A human-readable representation of the error.
target	string	The target of the error.

Azure.Core.Foundations.ErrorResponse

Object

A response containing error details.

Name	Type	Description
error	Azure.Core.Foundations.Error	The error object.

Azure.Core.Foundations.InnerError

Object

An object containing more specific information about the error. As per Azure REST API guidelines - https://aka.ms/AzureRestApiGuidelines#handling-errors.

Name	Type	Description
code	string	One of a server-defined set of error codes.
innererror	Azure.Core.Foundations.InnerError	Inner error.

AzureBlobContentSource

Object

Azure Blob Storage content. With the examples below, it represents files https://contoso.blob.core.windows.net/voicecontainer/jessica/*.wav

Name	Type	Description
containerUrl	string (uri)	Azure Blob Storage container URL with SAS. Need both read and list permissions.
extensions	string[]	File name extensions.
prefix	string	Blob name prefix.

Dataset

Object

Dataset object

Name	Type	Description
audios	AzureBlobContentSource	Azure Blob Storage content. With the examples below, it represents files `https://contoso.blob.core.windows.net/voicecontainer/jessica/*.wav`
description	string	Optional description of this dataset.
displayName	string	The name of this dataset.
kind	DatasetKind	Dataset kind
processAs	DatasetProcessAs	Dataset processing method. If not specified, the default processing method will be used.
scripts	AzureBlobContentSource	Azure Blob Storage content. With the examples below, it represents files `https://contoso.blob.core.windows.net/voicecontainer/jessica/*.wav`

DatasetKind

Enumeration

Dataset kind

Value	Description
AudioAndScript	AudioAndScript
LongAudio	LongAudio
AudioOnly	AudioOnly

DatasetProcessAs

Enumeration

Dataset processing method. If not specified, the default processing method will be used.

Value	Description
Segmented	The default processing mode that works with all supported languages.
Contextual	An enhanced mode that retains the audio as a whole to keep the contextual information for more natural intonations.