liveTranslate

Start, summarize, or stop live translation on the call. Live translation recognizes what each party says, translates it, and speaks the translation to the other party in place of the original audio. The action object takes the same shape as the live_translate SWML method: a single start, summarize, inject, or stop key.

See the translate calls guide for which language each party speaks and for the webhook events.

Parameters

action

Record<string, unknown>Required

The action to perform. Set exactly one of start, summarize, inject, or stop.

action.start

object

Start a live translation session.

action.start.from_lang

stringRequired

One of the two languages of the conversation, such as "es-ES". from_voice speaks it.

action.start.to_lang

stringRequired

The other language of the conversation, such as "en-US". to_voice speaks it.

action.start.direction

string[]Required

The sides of the call to translate: "remote-caller", "local-caller", or both. The order decides which side speaks which language.

action.start.webhook

string

The URL that receives translation events as HTTP POST requests.

action.start.from_voice

stringDefaults to azure.en-US-RyanMultilingualNeural

The voice that speaks translations into from_lang, as <engine>.<voice> with a lowercase engine name, such as "azure.es-ES-ElviraNeural".

action.start.to_voice

stringDefaults to azure.en-US-RyanMultilingualNeural

The voice that speaks translations into to_lang, such as "elevenlabs.josh".

action.start.filter_from

string

A tone filter for speech in from_lang: "polite", "rude", "professional", "shakespeare", "gen-z", or a custom instruction prefixed with "prompt:".

action.start.filter_to

string

A tone filter for speech in to_lang, with the same values as filter_from.

action.start.live_events

booleanDefaults to false

Whether to send each translated utterance to the webhook as it is spoken.

action.start.ai_summary

booleanDefaults to false

Whether to add AI summaries to the event sent to the webhook when the session ends.

action.start.ai_summary_prompt

string

The prompt that tells the AI how to summarize the conversation when ai_summary is enabled.

action.start.speech_engine

stringDefaults to deepgram

The speech recognition engine: "deepgram" or "google".

action.start.speech_timeout

numberDefaults to 60000

The timeout for speech recognition, in milliseconds.

action.start.vad_silence_ms

number

The silence, in milliseconds, that ends an utterance. Defaults to 700 with Deepgram and 500 with Google.

action.start.vad_thresh

numberDefaults to 400

Voice activity detection threshold, from 0 to 1800.

action.summarize

object

Request an AI summary of the conversation so far, while translation continues. Pass an empty object to send the summary to the webhook from start with the default summary prompt.

action.summarize.webhook

string

The URL that receives the summary.

action.summarize.prompt

string

The prompt that tells the AI how to summarize the conversation.

action.inject

object

Insert a message into the session, to be translated and spoken on the call.

action.inject.message

stringRequired

The message to translate and speak.

action.inject.direction

stringRequired

The side of the call: "remote-caller" or "local-caller".

action.stop

object

Stop the live translation session on both sides. Pass an empty object.

options

object

Optional settings for the command.

options.statusUrl

string

A status URL sent with the command. Translation events go to action.start.webhook.

Returns

Promise<Record<string, unknown>> — Server response confirming the operation.

Example

import { RelayClient } from '@signalwire/sdk';
const client = new RelayClient({
  project: process.env.SIGNALWIRE_PROJECT_ID!,
  token: process.env.SIGNALWIRE_API_TOKEN!,
  contexts: ['default']
});
client.onCall(async (call) => {
  await call.answer();
  // Start live translation between Spanish and English
  await call.liveTranslate({
    start: {
      from_lang: 'es-ES',
      to_lang: 'en-US',
      direction: ['local-caller', 'remote-caller'],
      webhook: 'https://example.com/translation-events',
    },
  });
  // Connect the caller to the other party, then let the call proceed...
  await call.waitForEnded();
});
await client.run();