Skip to navigation
FeaturesTTS Vendor Settings

Sarvam AI

Indic and Indian English voices, pace, pitch, loudness, temperature and pronunciation dictionaries for Sarvam TTS.

Sarvam AI generates speech in Indian English, Hindi and other Indic languages with its Bulbul models. The same Sarvam API key also serves speech recognition. Sarvam tuning is passed in synthesizer.options.

{
  "verb": "say",
  "text": "नमस्ते, आपकी booking confirm हो गई है।",
  "synthesizer": {
    "vendor": "sarvam",
    "language": "hi-IN",
    "voice": "kavya_hi_conversational",
    "options": {
      "pace": 1.0
    }
  }
}

You can also set these in the portal under Extra Options on the speech credential, in which case they apply to every request that uses that credential. Settings supplied on the verb take precedence.

Credential

Create an API key in your Sarvam account. jambonz sends it in the api-subscription-key header. Add it as a Sarvam AI speech credential in the portal or API; one credential is used for both text-to-speech and speech-to-text.

Models

ModelNotes
bulbul:v4-flashDefault. Persona voices such as simran_en_customer.
bulbul:v3Speakers such as shubh or kavya.
bulbul:v2Speakers such as anushka or abhilash.

Pick the model on the speech credential, or set options.model_id to override it for one verb.

Voices and languages

A bulbul:v4-flash voice is a persona id of the form <name>_<language>_<style>, such as simran_en_customer or kavya_hi_conversational. The portal lists the bulbul:v4-flash personas under each language; see Sarvam’s voice list for every model. Sarvam has no API for its preset voices, so the portal list is bundled with jambonz. A voice must belong to the model in use: a bulbul:v3 speaker does not work with bulbul:v4-flash.

Sarvam speaks bn-IN, en-IN, gu-IN, hi-IN, kn-IN, ml-IN, mr-IN, od-IN (Odia), pa-IN, ta-IN and te-IN. bulbul:v4-flash has no personas for ml-IN or od-IN yet. jambonz maps synthesizer.language to one of these codes: an exact match is used as-is, otherwise the base language is used with -IN (hi becomes hi-IN, en-US becomes en-IN, or-IN becomes od-IN), and any other language is sent as en-IN. Set options.language to choose explicitly; it takes precedence over synthesizer.language.

Options

model_id
string

The Bulbul model to use, overriding the credential’s model.

language
string

The language code sent to Sarvam, overriding synthesizer.language.

pace
number

Speaking rate relative to the voice’s normal speed.

pitch
number

Voice pitch. Sarvam documents it for bulbul:v2.

loudness
number

Voice loudness. Sarvam documents it for bulbul:v2.

temperature
number

Sampling temperature, for bulbul:v3 and bulbul:v4-flash.

enable_preprocessing
boolean

Turn on Sarvam’s text preprocessing (normalization) before synthesis.

dict_id
string

The id of a pronunciation dictionary in your Sarvam account.

Every option is optional. An option you don’t set is not sent, so Sarvam’s own default applies.

Streaming

These apply when Sarvam is driven by TTS streaming, for example from the agent verb.

min_buffer_size
number

Characters Sarvam buffers before it starts speaking, 30 – 200.

max_chunk_length
number

Maximum length of a synthesis chunk, 50 – 500 characters.

Non-streaming say

enable_cached_responses
boolean

Let Sarvam answer repeated text from its own cache. Sarvam marks this as beta.

Endpoint override

To point at a non-default endpoint, such as a proxy, set api_uri in the credential’s Extra Options; it applies to both TTS and STT. A ws:// or http:// prefix turns off TLS. Leave it out to use api.sarvam.ai.

Streaming

Sarvam supports TTS streaming, so it can be driven token by token from an LLM using tts:tokens, for example from the agent verb. Sarvam has no cancel message, so on barge-in jambonz closes the connection and opens a new one. Sarvam does not return word-level timestamps, so alignment events are not available.