GET

/v1/schemas/cartesia/audio/infill/bytes

Accept:

kind inputactivity audiohash acdf5f38…extracted Oct 30, 2026version currentsource upstream spec ↗

field	recorded source
schema	Source linked above. upstream-spec Source trace `a9ce21d0a3b28a57ef89ece81b676ac90c24bd222b3d9e2a9c10d00b53fe8205` { "fetchedAt": 1793337635, "extractorVersion": "1", "verifiedAt": null }

Request body

10 properties · 0 required · 3 $defs

property	type	description	constraints
left_audio	string	Audio clip that comes before the infill transcript: `left_audio` -> `transcript` -> `right_audio`	format: binary
right_audio	string	Audio clip that comes after the infill transcript: `left_audio` -> `transcript` -> `right_audio`	format: binary
model_id	enum	The ID of the model to use for generating audio	sonic-3 \| sonic-3-2026-01-12
language	enum	The language of the transcript	en \| fr \| de \| es \| pt \| zh · +38 more
transcript	string	The infill text to generate. For best results, use longer transcripts to give the model more flexibility to adapt to the rest of the audio.
voice_id	string	The ID of the voice to use for generating audio
output_format[container]	enum	The format of the output audio	raw \| wav \| mp3
output_format[sample_rate]	enum	The sample rate of the output audio	8000 \| 16000 \| 22050 \| 24000 \| 44100 \| 48000
output_format[encoding]	enum	Required for `raw` and `wav` containers.	pcm_f32le \| pcm_s16le \| pcm_mulaw \| pcm_alaw
output_format[bit_rate]	integer	Required for `mp3` containers.

Types

3 $defs

OutputFormatContainerenum

raw | wav | mp3

RawEncodingenum

The encoding format for output audio. See [TTS Output Audio Format](/build-with-cartesia/capability-guides/tts-output-audio-format) if you're unsure what to use.

pcm_f32le | pcm_s16le | pcm_mulaw | pcm_alaw

SupportedLanguageenum

The language that the given voice should speak the transcript in. This may depend on the model you're using. See [Models](/build-with-cartesia/tts-models/latest) for details.

en | fr | de | es | pt | zh · +38 more

Validate a payload

before you spend tokens

shell

$ curl -X POST https://modelschemas.com/v1/validate \
    -d '{"provider":"cartesia","endpointId":"infill/bytes","payload":{…}}'
→ {"valid": false, "errors": [{"path": "#", "keyword": "required", …}]}