Sarvam

The SarvamVoice class in Mastra provides text-to-speech and speech-to-text capabilities using Sarvam AI models.

Usage example

import { SarvamVoice } from '@mastra/voice-sarvam'

// Initialize with default configuration using environment variables
const voice = new SarvamVoice()

// Or initialize with specific configuration
const voiceWithConfig = new SarvamVoice({
  speechModel: {
    model: 'bulbul:v3',
    apiKey: process.env.SARVAM_API_KEY!,
    language: 'en-IN',
    properties: {
      pace: 1.0,
      temperature: 0.6,
      speech_sample_rate: 24000,
      output_audio_codec: 'wav',
    },
  },
  listeningModel: {
    model: 'saarika:v2.5',
    apiKey: process.env.SARVAM_API_KEY!,
    languageCode: 'en-IN',
    filetype: 'wav',
  },
  speaker: 'shubh', // Default voice for bulbul:v3
})

// Convert text to speech
const audioStream = await voice.speak('Hello, how can I help you?')

// Convert speech to text
const text = await voice.listen(audioStream, {
  filetype: 'wav',
})

Sarvam API Docs -

https://docs.sarvam.ai/api-reference-docs/text-to-speech/convert

Configuration

Constructor options

speechModel?:

SarvamVoiceConfig

= { model: 'bulbul:v3', language: 'en-IN' }

Configuration for text-to-speech synthesis.

SarvamVoiceConfig

apiKey?:

string

Sarvam API key. Falls back to SARVAM_API_KEY environment variable.

model?:

SarvamTTSModel

Specifies the model to use for text-to-speech conversion. Available options: bulbul:v2, bulbul:v3, bulbul:v3-beta. bulbul:v3-beta is a beta variant of bulbul:v3 that shares the same speaker catalog. Note: bulbul:v1 has been deprecated by Sarvam and is no longer supported.

language:

SarvamTTSLanguage

Target language for speech synthesis. Available options: hi-IN, bn-IN, kn-IN, ml-IN, mr-IN, od-IN, pa-IN, ta-IN, te-IN, en-IN, gu-IN

properties?:

object

Additional voice properties for customization.

properties.pace?:

number

Controls the speed of the audio. Supported by both bulbul:v2 (range 0.3–3.0) and bulbul:v3 (range 0.5–2.0).

properties.temperature?:

number

Sampling temperature that controls the randomness of the generated voice. bulbul:v3 only. Range: 0.01–2.0. Default: 0.6.

properties.dict_id?:

string

Pronunciation dictionary ID. bulbul:v3 only.

properties.pitch?:

number

Controls the pitch of the audio. Lower values result in a deeper voice, while higher values make it sharper. bulbul:v2 only. Range: -0.75 to 0.75.

properties.loudness?:

number

Controls the loudness of the audio. bulbul:v2 only. Range: 0.3 to 3.0.

properties.enable_preprocessing?:

boolean

Enables normalization of English words and numeric entities (numbers, dates, etc.). bulbul:v2 only. Default is false.

properties.speech_sample_rate?:

8000 | 16000 | 22050 | 24000 | 32000 | 44100 | 48000

Audio sample rate in Hz.

properties.output_audio_codec?:

'mp3' | 'wav' | 'linear16' | 'mulaw' | 'alaw' | 'opus' | 'flac' | 'aac'

Output audio codec.

speaker?:

SarvamVoiceId

= 'shubh'

The speaker to be used for the output audio. Defaults to 'shubh'. bulbul:v3 supports 39 voices (shubh, aditya, ritu, priya, neha, rahul, pooja, rohan, simran, kavya, amit, dev, ishita, shreya, ratan, varun, manan, sumit, roopa, kabir, aayan, ashutosh, advait, amelia, sophia, anand, tanya, tarun, sunny, mani, gokul, vijay, shruti, suhani, mohit, kavitha, rehan, soham, rupali). bulbul:v2 supports 7 voices (anushka, manisha, vidya, arya, abhilash, karun, hitesh). Speakers are not interchangeable between model versions.

listeningModel?:

SarvamListenOptions

= { model: 'saarika:v2.5', languageCode: 'unknown' }

Configuration for speech-to-text recognition.

SarvamListenOptions

apiKey?:

string

Sarvam API key. Falls back to SARVAM_API_KEY environment variable.

model?:

SarvamSTTModel

Specifies the model to use for speech-to-text conversion. Available options: saarika:v2.5 (transcription), saaras:v3 (multi-mode: transcribe/translate/verbatim/translit/codemix). Note: saarika:v1, saarika:v2, and saarika:flash have been deprecated by Sarvam.

languageCode?:

SarvamSTTLanguage

BCP-47 language code of the input audio. Optional for saarika:v2.5 and saaras:v3 (the API will detect the language automatically when 'unknown' is passed). Available options: unknown, hi-IN, bn-IN, kn-IN, ml-IN, mr-IN, od-IN, pa-IN, ta-IN, te-IN, en-IN, gu-IN.

filetype?:

'mp3' | 'wav'

Audio format of the input stream.

mode?:

SarvamSTTMode

Operation mode. Only valid when using the saaras:v3 model; ignored by saarika:v2.5. Available options: 'transcribe', 'translate', 'verbatim', 'translit', 'codemix'.

Methods

speak()

Converts text to speech using Sarvam's text-to-speech models.

input:

string | NodeJS.ReadableStream

Text or text stream to convert to speech.

options?:

Options

Configuration options.

Options

speaker?:

SarvamVoiceId

Voice ID to use for speech synthesis.

Returns: Promise<NodeJS.ReadableStream>

listen()

Transcribes audio using Sarvam's speech recognition models.

input:

NodeJS.ReadableStream

Audio stream to transcribe.

options?:

SarvamListenOptions

Configuration options for speech recognition.

Returns: Promise<string>

getSpeakers()

Returns an array of available voice options.

Returns: Promise<Array<{voiceId: SarvamVoiceId}>>

Notes

• API key can be provided via constructor options or the SARVAM_API_KEY environment variable
• If no API key is provided, the constructor will throw an error
• The service communicates with the Sarvam AI API at https://api.sarvam.ai
• Audio is returned as a stream containing binary audio data
• Speech recognition supports mp3 and wav audio formats
• bulbul:v1, saarika:v1, saarika:v2, and saarika:flash have been deprecated by Sarvam and are no longer supported. Use bulbul:v3 (or bulbul:v2) for TTS and saarika:v2.5 (or saaras:v3) for STT.
• Speaker names are not interchangeable between bulbul:v2 and bulbul:v3 — each model version has its own speaker catalog.