WebSockets

The Text-to-Speech WebSockets API is designed to generate audio from partial text input while ensuring consistency throughout the generated audio. Although highly flexible, the WebSockets API isn’t a one-size-fits-all solution. It’s well-suited for scenarios where:

  • The input text is being streamed or generated in chunks.
  • Word-to-audio alignment information is required.

However, it may not be the best choice when:

  • The entire input text is available upfront. Given that the generations are partial, some buffering is involved, which could potentially result in slightly higher latency compared to a standard HTTP request.
  • You want to quickly experiment or prototype. Working with WebSockets can be harder and more complex than using a standard HTTP API, which might slow down rapid development and testing.

HandshakeTry it

GET
/v1/text-to-speech/:voice_id/stream-input

Headers

xi-api-keystringOptional

Path parameters

voice_idstringRequired

The unique identifier for the voice to use in the TTS process.

Query parameters

authorizationstringOptional

Your authorization bearer token.

model_idstringOptional

The model ID to use.

language_codestringOptional

The ISO 639-1 language code (for specific models).

enable_loggingbooleanOptionalDefaults to true

Whether to enable logging of the request.

enable_ssml_parsingbooleanOptionalDefaults to false

Whether to enable SSML parsing.

output_formatenumRequired

The output audio format

inactivity_timeoutintegerOptionalDefaults to 20

Timeout for inactivity before a context is closed (seconds), can be up to 180 seconds.

sync_alignmentbooleanOptionalDefaults to false

Whether to include timing data with every audio chunk.

auto_modebooleanOptionalDefaults to false

Reduces latency by disabling chunk schedule and buffers. Recommended for full sentences/phrases.

apply_text_normalizationenumRequired

This parameter controls text normalization with three modes - ‘auto’, ‘on’, and ‘off’. When set to ‘auto’, the system will automatically decide whether to apply text normalization (e.g., spelling out numbers). With ‘on’, text normalization will always be applied, while with ‘off’, it will be skipped. Cannot be turned on for ‘eleven_turbo_v2_5’ or ‘eleven_flash_v2_5’ models. Defaults to ‘auto’.

Allowed values:
seedintegerOptional>=0

If specified, system will best-effort sample deterministically. Integer between 0 and 4294967295.

Send

objectRequired
OR
objectRequired
OR
objectRequired

Receive

objectRequired
OR
objectRequired