Flux Text to Speech (batch)

POST https://api.deepgram.com/v2/speak Content-Type: application/json

Synthesize a complete block of text into a single audio response using Deepgram's Flux TTS batch (REST) API. Use this for pre-rendering fixed audio (IVR prompts, notifications, narration) where the whole text is known up front and you don't need incremental playback or interruption.

Reference: https://developers.deepgram.com/reference/speak/v-2/audio/generate

• Authorization header (required) (prefixed with Token ) — Use Authorization: Token <API_KEY> Example: Authorization: Token 12345abcdef
• Authorization header (bearer token, required) — Use Authorization: Bearer <JWT> Example: Authorization: Bearer eyJhbGciOiJ...

• callback (string, optional) — URL to which we'll make the callback request
• callback_method (enum, optional, default: POST) — HTTP method by which the callback request will be made
  • Allowed values: POST, PUT
• mip_opt_out (boolean, optional, default: false) — Opts out requests from the Deepgram Model Improvement Program. Refer to our Docs for pricing impacts before setting this to true. https://dpgr.am/deepgram-mip
• tag (V2SpeakPostParametersTag, optional) — Label your requests for the purpose of identification during usage reporting
• bit_rate (V2SpeakPostParametersBitRate, optional, default: 48000) — The bitrate of the audio in bits per second. Choose from predefined ranges or specific values based on the encoding type.
• container (V2SpeakPostParametersContainer, optional, default: wav) — Container specifies the file format wrapper for the output audio. The available options depend on the encoding type.
• encoding (V2SpeakPostParametersEncoding, optional, default: mp3) — Encoding allows you to specify the expected encoding of your audio output
• expressivity (enum, optional, default: 0) — Expressive range of the generated speech, on a calm-to-animated axis. Accepted values: -2, -1, 0, 1, 2. 0 (the default) is the voice's tuned delivery and the production-validated setting, with -2 the calm end of the range and 2 the animated end. Supported on all Flux voices; applies to the whole request. Beta: behavior may change in future model versions, and non-default values increase the risk of hallucinations and pronunciation errors; audition before shipping. An invalid value is rejected with a 400 — EXPRESSIVITY_OUT_OF_RANGE for a value outside the range, EXPRESSIVITY_INCREMENT_INVALID for a fractional value. See Expressivity.
  • Allowed values: -2, -1, 0, 1, 2
• model (string, required) — Flux TTS model used to synthesize the submitted text, in the form flux-{voice}-{language} (for example, flux-alexis-en). Required; unlike the v1 (Aura) endpoint there is no default and only flux models are accepted. English-only at launch.
• sample_rate (V2SpeakPostParametersSampleRate, optional, default: 24000) — Sample Rate specifies the sample rate for the output audio. Based on the encoding, different sample rates are supported. For some encodings, the sample rate is not configurable
• speed (double, optional, default: 1) — Speaking rate multiplier that adjusts the pace of generated speech while preserving natural prosody and voice quality. Accepted values run 0.5 to 1.5 in 0.05 increments. Not yet supported in all languages.
• priority (enum, optional) — Processing priority for asynchronous (callback) requests. The only supported value is low.
  • Allowed values: low

This endpoint expects a SpeakV2Request.

• text (string, required) — The text content to be converted to speech. The server normalizes and preprocesses the text before synthesis. Inline pause and pronunciation controls are not yet applied; they are stripped from the text before synthesis.

Returns the synthesized audio in the requested encoding as a binary stream. When a callback URL is supplied, the request is processed asynchronously and the response body is instead a JSON acknowledgement (Content-Type application/json) of the form {"request_id": "..."}, with the audio delivered to the callback URL. Because this endpoint is typed as a binary audio stream, SDK callers that set callback receive this JSON acknowledgement through the audio byte iterator as raw bytes and must join the chunks and parse request_id themselves.

• request_id (string, required) — Unique identifier for tracking the asynchronous request

Invalid Request. Inline pause and pronunciation controls are not applied and are stripped rather than rejected.

• ErrorResponse

• err_code (string, optional) — The error code
• err_msg (string, optional) — The error message
• request_id (string, optional) — The request ID

• category (string, optional) — The category of the error
• message (string, optional) — A message about the error
• details (string, optional) — A description of the error
• request_id (string, optional) — The unique identifier of the request

Request

{
  "text": "Your appointment is confirmed for 3pm tomorrow."
}

Response

{
  "request_id": "a1b2c3d4-e5f6-7890-ab12-cd34ef567890"
}

SDK Code

import requests

url = "https://api.deepgram.com/v2/speak"

querystring = {"expressivity":"1","model":"flux-alexis-en","speed":"1.05"}

payload = { "text": "Your appointment is confirmed for 3pm tomorrow." }
headers = {
    "Authorization": "Token <apiKey>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers, params=querystring)

print(response.json())

const url = 'https://api.deepgram.com/v2/speak?expressivity=1&model=flux-alexis-en&speed=1.05';
const options = {
  method: 'POST',
  headers: {Authorization: 'Token <apiKey>', 'Content-Type': 'application/json'},
  body: '{"text":"Your appointment is confirmed for 3pm tomorrow."}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.deepgram.com/v2/speak?expressivity=1&model=flux-alexis-en&speed=1.05"

	payload := strings.NewReader("{\n  \"text\": \"Your appointment is confirmed for 3pm tomorrow.\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Token <apiKey>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}

require 'uri'
require 'net/http'

url = URI("https://api.deepgram.com/v2/speak?expressivity=1&model=flux-alexis-en&speed=1.05")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Token <apiKey>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"text\": \"Your appointment is confirmed for 3pm tomorrow.\"\n}"

response = http.request(request)
puts response.read_body

import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://api.deepgram.com/v2/speak?expressivity=1&model=flux-alexis-en&speed=1.05")
  .header("Authorization", "Token <apiKey>")
  .header("Content-Type", "application/json")
  .body("{\n  \"text\": \"Your appointment is confirmed for 3pm tomorrow.\"\n}")
  .asString();

<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.deepgram.com/v2/speak?expressivity=1&model=flux-alexis-en&speed=1.05', [
  'body' => '{
  "text": "Your appointment is confirmed for 3pm tomorrow."
}',
  'headers' => [
    'Authorization' => 'Token <apiKey>',
    'Content-Type' => 'application/json',
  ],
]);

echo $response->getBody();

using RestSharp;

var client = new RestClient("https://api.deepgram.com/v2/speak?expressivity=1&model=flux-alexis-en&speed=1.05");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Token <apiKey>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{\n  \"text\": \"Your appointment is confirmed for 3pm tomorrow.\"\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);

import Foundation

let headers = [
  "Authorization": "Token <apiKey>",
  "Content-Type": "application/json"
]
let parameters = ["text": "Your appointment is confirmed for 3pm tomorrow."] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://api.deepgram.com/v2/speak?expressivity=1&model=flux-alexis-en&speed=1.05")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()