POST
/
v1
/
text-to-speech
/
{voice_id}
/
with-timestamps

​
Character-Level Speech Timestamps

Generate audio with character-level timing information, which allows you to synchronize text with audio playback. This is useful for applications like karaoke, subtitles, or word-by-word highlighting. Here’s how to use it:

The response includes the audio data and a timestamp dictionary:

{
    'characters': ['H', 'e', 'l', 'l', 'o', '!', ...],
    'character_start_times_seconds': [0.0, 0.186, 0.279, 0.348, 0.406, 0.441, ...],
    'character_end_times_seconds': [0.186, 0.279, 0.348, 0.406, 0.441, 0.476, ...]
}

Each character’s timing is provided in seconds, enabling precise synchronization between text and audio. For instance, the character ‘l’ begins at 0.348 seconds and ends at 0.406 seconds in the audio output.

Headers

xi-api-key
string

Your API key. This is required by most endpoints to access our API programatically. You can view your xi-api-key using the 'Profile' tab on the website.

Path Parameters

voice_id
string
required

Voice ID to be used, you can use https://api.elevenlabs.io/v1/voices to list all the available voices.

Query Parameters

enable_logging
boolean
default: true

When enable_logging is set to false full privacy mode will be used for the request. This will mean history features are unavailable for this request, including request stitching. Full privacy mode may only be used by enterprise customers.

optimize_streaming_latency
integer
deprecated

You can turn on latency optimizations at some cost of quality. The best possible final latency varies by model. Possible values: 0 - default mode (no latency optimizations) 1 - normal latency optimizations (about 50% of possible latency improvement of option 3) 2 - strong latency optimizations (about 75% of possible latency improvement of option 3) 3 - max latency optimizations 4 - max latency optimizations, but also with text normalizer turned off for even more latency savings (best latency, but can mispronounce eg numbers and dates).

Defaults to None.

output_format
string
default: mp3_44100_128

Output format of the generated audio. Must be one of: mp3_22050_32 - output format, mp3 with 22.05kHz sample rate at 32kbps. mp3_44100_32 - output format, mp3 with 44.1kHz sample rate at 32kbps. mp3_44100_64 - output format, mp3 with 44.1kHz sample rate at 64kbps. mp3_44100_96 - output format, mp3 with 44.1kHz sample rate at 96kbps. mp3_44100_128 - default output format, mp3 with 44.1kHz sample rate at 128kbps. mp3_44100_192 - output format, mp3 with 44.1kHz sample rate at 192kbps. Requires you to be subscribed to Creator tier or above. pcm_16000 - PCM format (S16LE) with 16kHz sample rate. pcm_22050 - PCM format (S16LE) with 22.05kHz sample rate. pcm_24000 - PCM format (S16LE) with 24kHz sample rate. pcm_44100 - PCM format (S16LE) with 44.1kHz sample rate. Requires you to be subscribed to Pro tier or above. ulaw_8000 - μ-law format (sometimes written mu-law, often approximated as u-law) with 8kHz sample rate. Note that this format is commonly used for Twilio audio inputs.

Body

application/json
text
string
required

The text that will get converted into speech.

model_id
string
default: eleven_monolingual_v1

Identifier of the model that will be used, you can query them using GET /v1/models. The model needs to have support for text to speech, you can check this using the can_do_text_to_speech property.

language_code
string

Language code (ISO 639-1) used to enforce a language for the model. Currently only Turbo v2.5 supports language enforcement. For other models, an error will be returned if language code is provided.

voice_settings
object

Voice settings overriding stored setttings for the given voice. They are applied only on the given request.

pronunciation_dictionary_locators
object[]

A list of pronunciation dictionary locators (id, version_id) to be applied to the text. They will be applied in order. You may have up to 3 locators per request

seed
integer

If specified, our system will make a best effort to sample deterministically, such that repeated requests with the same seed and parameters should return the same result. Determinism is not guaranteed.

previous_text
string

The text that came before the text of the current request. Can be used to improve the flow of prosody when concatenating together multiple generations or to influence the prosody in the current generation.

next_text
string

The text that comes after the text of the current request. Can be used to improve the flow of prosody when concatenating together multiple generations or to influence the prosody in the current generation.

previous_request_ids
string[]

A list of request_id of the samples that were generated before this generation. Can be used to improve the flow of prosody when splitting up a large task into multiple requests. The results will be best when the same model is used across the generations. In case both previous_text and previous_request_ids is send, previous_text will be ignored. A maximum of 3 request_ids can be send.

next_request_ids
string[]

A list of request_id of the samples that were generated before this generation. Can be used to improve the flow of prosody when splitting up a large task into multiple requests. The results will be best when the same model is used across the generations. In case both next_text and next_request_ids is send, next_text will be ignored. A maximum of 3 request_ids can be send.

use_pvc_as_ivc
boolean
default: falsedeprecated

If true, we won't use PVC version of the voice for the generation but the IVC version. This is a temporary workaround for higher latency in PVC versions.

apply_text_normalization
enum<string>
default: auto

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' model.

Available options:
auto,
on,
off

Response

200 - application/json
audio_base64
string

Base64 encoded audio data

alignment
object
normalized_alignment
object

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