V-Blaze and V-Cloud Online Help (May 2020)

Getting Started

Using the cURL Utility

All examples shown in this document use cURL, a command line utility that sends HTTP client requests. The cURL application is freely available for Linux, Windows, and macOS operating systems.


Escaped newlines, which are lines in the cURL command or the example output that end with a backslash (/), are added for readability. Escaped newlines must not be present in cURL commands and are not included in the commands' output.

Submitting Transcription Requests

A transcription session is initiated by issuing an HTTP POST to the appropriate URL. The following is an example cURL command using the previously specified URL:


Where vblaze_name is the name of your V‑Blaze server.


The V‑Blaze REST API service monitors port 17171 by default, but this can be changed if necessary. If transmission encryption is required you can use HTTPS rather than HTTP.

The POST must be encoded as a multipart HTTP request with the audio to be transcribed specified in the file field. As an example using the cURL command, our base URL example would be generated as follows:

curl -F file=@/path/to/sample1.wav \

All major programming languages provide support for generating multipart HTTP requests.

Receiving Transcription Results

The transcript is returned in the HTTP response to a POST call to the /transcribe method by default. Optionally, transcripts can be returned via HTTP POST; this method is known as a "callback" and is described in Receiving Results via Callback.


The file field must be the last field specified in the request, as shown in the following example.

Example HTTP Response


Transcribe a short audio file and return text in the HTTP response.


curl -F output=text \
     -F model=eng1:callcenter \
     -F file=@sample7.wav \


    Thank you for calling center point energy technical support. I understand you need to report a gas leak and I have your name please. My name is Joe. What is your address or account number my address and then one Martin Houston, Texas is there. Anyone inside the house? I know everyone is out of the house. I notice the strange smell when I got home and I called you I am sending and gas technician to your home to fix the problem. Could you give me a good number to reach you at. You can call 28195345. Thank you, please be safe and wait for the technician to arrive call us back if anything changes. Thank you, bye. Good bye and thank you for calling center point energy.