Lightning v3.1 SSE

Stream speech from text (Lightning V3.1)

curl --request POST \
  --url https://api.smallest.ai/waves/v1/lightning-v3.1/stream \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "text": "<string>",
  "voice_id": "<string>",
  "sample_rate": 44100,
  "speed": 1,
  "language": "auto",
  "output_format": "pcm",
  "pronunciation_dicts": [
    "<string>"
  ]
}
'

import requests

url = "https://api.smallest.ai/waves/v1/lightning-v3.1/stream"

payload = {
    "text": "<string>",
    "voice_id": "<string>",
    "sample_rate": 44100,
    "speed": 1,
    "language": "auto",
    "output_format": "pcm",
    "pronunciation_dicts": ["<string>"]
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    text: '<string>',
    voice_id: '<string>',
    sample_rate: 44100,
    speed: 1,
    language: 'auto',
    output_format: 'pcm',
    pronunciation_dicts: ['<string>']
  })
};

fetch('https://api.smallest.ai/waves/v1/lightning-v3.1/stream', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.smallest.ai/waves/v1/lightning-v3.1/stream",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'text' => '<string>',
    'voice_id' => '<string>',
    'sample_rate' => 44100,
    'speed' => 1,
    'language' => 'auto',
    'output_format' => 'pcm',
    'pronunciation_dicts' => [
        '<string>'
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

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

func main() {

	url := "https://api.smallest.ai/waves/v1/lightning-v3.1/stream"

	payload := strings.NewReader("{\n  \"text\": \"<string>\",\n  \"voice_id\": \"<string>\",\n  \"sample_rate\": 44100,\n  \"speed\": 1,\n  \"language\": \"auto\",\n  \"output_format\": \"pcm\",\n  \"pronunciation_dicts\": [\n    \"<string>\"\n  ]\n}")

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

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

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.smallest.ai/waves/v1/lightning-v3.1/stream")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"text\": \"<string>\",\n  \"voice_id\": \"<string>\",\n  \"sample_rate\": 44100,\n  \"speed\": 1,\n  \"language\": \"auto\",\n  \"output_format\": \"pcm\",\n  \"pronunciation_dicts\": [\n    \"<string>\"\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.smallest.ai/waves/v1/lightning-v3.1/stream")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"text\": \"<string>\",\n  \"voice_id\": \"<string>\",\n  \"sample_rate\": 44100,\n  \"speed\": 1,\n  \"language\": \"auto\",\n  \"output_format\": \"pcm\",\n  \"pronunciation_dicts\": [\n    \"<string>\"\n  ]\n}"

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

{
  "data": "event: chunk\ndata: <WAV_DATA>\ndone: false\n"
}

{
  "error": "InvalidRequest",
  "message": "The 'text' field is required."
}

{
  "error": "Unauthorized",
  "message": "Bearer token is missing or invalid."
}

{
  "error": "InternalServerError",
  "message": "An unexpected error occurred."
}

POST

waves

lightning-v3.1

stream

Stream speech from text (Lightning V3.1)

curl --request POST \
  --url https://api.smallest.ai/waves/v1/lightning-v3.1/stream \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "text": "<string>",
  "voice_id": "<string>",
  "sample_rate": 44100,
  "speed": 1,
  "language": "auto",
  "output_format": "pcm",
  "pronunciation_dicts": [
    "<string>"
  ]
}
'

import requests

url = "https://api.smallest.ai/waves/v1/lightning-v3.1/stream"

payload = {
    "text": "<string>",
    "voice_id": "<string>",
    "sample_rate": 44100,
    "speed": 1,
    "language": "auto",
    "output_format": "pcm",
    "pronunciation_dicts": ["<string>"]
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    text: '<string>',
    voice_id: '<string>',
    sample_rate: 44100,
    speed: 1,
    language: 'auto',
    output_format: 'pcm',
    pronunciation_dicts: ['<string>']
  })
};

fetch('https://api.smallest.ai/waves/v1/lightning-v3.1/stream', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.smallest.ai/waves/v1/lightning-v3.1/stream",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'text' => '<string>',
    'voice_id' => '<string>',
    'sample_rate' => 44100,
    'speed' => 1,
    'language' => 'auto',
    'output_format' => 'pcm',
    'pronunciation_dicts' => [
        '<string>'
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

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

func main() {

	url := "https://api.smallest.ai/waves/v1/lightning-v3.1/stream"

	payload := strings.NewReader("{\n  \"text\": \"<string>\",\n  \"voice_id\": \"<string>\",\n  \"sample_rate\": 44100,\n  \"speed\": 1,\n  \"language\": \"auto\",\n  \"output_format\": \"pcm\",\n  \"pronunciation_dicts\": [\n    \"<string>\"\n  ]\n}")

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

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

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.smallest.ai/waves/v1/lightning-v3.1/stream")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"text\": \"<string>\",\n  \"voice_id\": \"<string>\",\n  \"sample_rate\": 44100,\n  \"speed\": 1,\n  \"language\": \"auto\",\n  \"output_format\": \"pcm\",\n  \"pronunciation_dicts\": [\n    \"<string>\"\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.smallest.ai/waves/v1/lightning-v3.1/stream")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"text\": \"<string>\",\n  \"voice_id\": \"<string>\",\n  \"sample_rate\": 44100,\n  \"speed\": 1,\n  \"language\": \"auto\",\n  \"output_format\": \"pcm\",\n  \"pronunciation_dicts\": [\n    \"<string>\"\n  ]\n}"

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

{
  "data": "event: chunk\ndata: <WAV_DATA>\ndone: false\n"
}

{
  "error": "InvalidRequest",
  "message": "The 'text' field is required."
}

{
  "error": "Unauthorized",
  "message": "Bearer token is missing or invalid."
}

{
  "error": "InternalServerError",
  "message": "An unexpected error occurred."
}

Overview

The Lightning v3.1 SSE API provides real-time text-to-speech streaming capabilities with natural, expressive voice synthesis. This API uses Server-Sent Events (SSE) to deliver audio chunks as they’re generated, enabling low-latency audio playback without waiting for the entire audio file to process. Lightning v3.1 is a 44 kHz model that produces natural, expressive, and realistic speech, with support for voice cloning.

When to Use

Interactive Applications: Perfect for chatbots, virtual assistants, and other applications requiring immediate voice responses
Long-Form Content: Efficiently stream audio for articles, stories, or other long-form content without buffering delays
Voice User Interfaces: Create natural-sounding voice interfaces with minimal perceived latency
Accessibility Solutions: Provide real-time audio versions of written content for users with visual impairments

How It Works

Make a POST Request: Send your text and voice settings to the API endpoint
Receive Audio Chunks: The API processes your text and streams audio back as base64-encoded chunks with 1024 byte size
Process the Stream: Handle the SSE events to decode and play audio chunks sequentially
End of Stream: The API sends a completion event when all audio has been delivered

Authorizations

Authorization

string

header

required

Bearer authentication header of the form Bearer <api_key>, where <api_key> is your api key.

Body

application/json

text

string

required

The text to convert to speech.

voice_id

string

required

The voice identifier to use for speech generation.

sample_rate

enum<integer>

default:44100

The sample rate for the generated audio.

Available options:

8000,

16000,

24000,

44100

speed

number

default:1

The speed of the generated speech.

Required range: 0.5 <= x <= 2

language

enum<string>

default:auto

Language code for text normalization (e.g., how numbers, dates, and abbreviations are spelled out). Set to 'auto' for automatic language detection, or specify a language code like 'en' or 'hi'.

Available options:

auto,

en,

hi,

ta,

es

output_format

enum<string>

default:pcm

The format of the output audio.

Available options:

pcm,

mp3,

wav,

mulaw

pronunciation_dicts

string[]

The IDs of the pronunciation dictionaries to use for speech generation.

The ID of the pronunciation dictionary to use for speech generation.

Response

Synthesized speech retrieved successfully.

Lightning v3.1 Lightning v3.1 WebSocket

API References

Text to Speech

Speech to Text

Voices

Voice Cloning

Pronunciation Dictionaries

Lightning v3.1 SSE

Overview

When to Use

How It Works

Authorizations

Body

Response

​Overview

​When to Use

​How It Works

Authorizations

Body

Response

Overview

When to Use

How It Works