Upload Audio Asset | SpeechifyAI API

Upload a new audio asset. The body is a multipart/form-data request with a single file field carrying the WAV bytes.

The WAV is validated server-side against a strict format contract — PCM 16-bit signed, mono, 48000 Hz, ≤30s, ≤4 MiB — before any bytes hit storage. The format matches what voice agents play back natively, so clips stream with no transcoding; convert MP3 sources with ffmpeg -i in.mp3 -ar 48000 -ac 1 -sample_fmt s16 out.wav.

Upload a new audio asset. The body is a multipart/form-data request with a single `file` field carrying the WAV bytes. The WAV is validated server-side against a strict format contract — PCM 16-bit signed, mono, 48000 Hz, ≤30s, ≤4 MiB — before any bytes hit storage. The format matches what voice agents play back natively, so clips stream with no transcoding; convert MP3 sources with `ffmpeg -i in.mp3 -ar 48000 -ac 1 -sample_fmt s16 out.wav`.

Authentication

AuthorizationBearer

Enter your API key with the Bearer prefix, e.g. ‘Bearer sk_…’.

Headers

Speechify-VersionstringOptional

Request

This endpoint expects a multipart form containing a file.

filefileRequired

The WAV file bytes. Must be PCM 16-bit signed, mono, 48000 Hz, ≤30s duration, ≤4 MiB total.

Response headers

X-Request-IDstring

Unique identifier for this request, present on every response (2xx and non-2xx alike). If the caller sends an X-Request-ID request header the server echoes it back (sanitized and length-capped) so one logical request can be traced end-to-end; otherwise the server generates a fresh value. Log it on every response and quote it in support requests - it is the stable handle that ties your observation to Speechify’s server-side logs, and it matches the request_id field in the error envelope.

Unique identifier for this request, present on every response (2xx and non-2xx alike). If the caller sends an `X-Request-ID` request header the server echoes it back (sanitized and length-capped) so one logical request can be traced end-to-end; otherwise the server generates a fresh value. Log it on every response and quote it in support requests - it is the stable handle that ties your observation to Speechify's server-side logs, and it matches the `request_id` field in the error envelope.

Response

The uploaded asset's metadata.

idstringformat: "^audio_[0-9a-hjkmnp-tv-z]{26}$"

Prefixed wire identifier (audio_<26 char Crockford base32>). URL paths accept only this prefixed form; legacy UUID path parameters are rejected with 404.

original_filenamestring

The filename supplied at upload time, kept for display.

content_typestring

Always audio/wav. Pinned server-side after WAV validation rather than trusting the upload’s multipart Content-Type header.

size_bytesinteger

Stored byte length. Capped at 4 MiB at upload time.

duration_msinteger

Clip duration in milliseconds. Capped at 30000 (30s) at upload time.

sample_rate_hzinteger

WAV sample rate. Always 48000 (the rate voice agents play back natively).

channelsinteger

Channel count. Always 1 (mono).

bit_depthinteger

PCM sample bit depth. Always 16.

created_atdatetime

Errors

400

Bad Request Error

401

Unauthorized Error

$	curl -X POST https://api.speechify.ai/v1/agents/audio-assets \
>	-H "Authorization: Bearer <token>" \
>	-H "Content-Type: multipart/form-data" \
>	-F file=@example

1	{
2	"id": "audio_01kb48ey4hdd14htwf32bjq85q",
3	"original_filename": "example",
4	"content_type": "example",
5	"size_bytes": 1024,
6	"duration_ms": 5000,
7	"sample_rate_hz": 48000,
8	"channels": 1,
9	"bit_depth": 1,
10	"created_at": "2026-06-24T18:03:11Z"
11	}