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Telnyx x402 Gateway – Audio Transcription (Speech-to-Text)
x402
Telnyx x402 Gateway – Audio Transcription (Speech-to-Text) is a paid API for AI agents from x402.telnyx.com, paid per call via x402, $0.015/call, status unknown (last checked 2026-10-12).
Transcribes an audio file (WAV or MP3) to text using Whisper large-v3-turbo, billed at $0.015 USDC per call via the x402 payment protocol.
Price / call$0.015
Success—
StatusUnknown
How this service works
Pay USDC per request for Telnyx Inference and Audio (text-to-speech, speech-to-text) through x402.
Output
A JSON object containing the full transcribed text string, total audio duration in seconds, and an array of segments each with start/end times and the text spoken in that segment. When response_format is 'json', only the text field is returned.
Example use cases
Meeting recording transcript with timestamps
“I have an MP3 of a 3-minute team standup meeting. Transcribe it using Whisper and give me verbose_json output with segment timestamps so I can see who said what and when — the audio is in English.”
Multilingual customer call transcription
“Can you transcribe this WAV file of a customer support call? It's in Spanish, so pass 'es' as the language hint, and return the result as plain json text — I just need the words, no timestamps.”
Voice memo to searchable text
“Turn this short voice memo MP3 into text for me. Use whisper-1 and give me back just the transcript text in json format so I can paste it into my notes app.”
Technical details
Endpoint
POSThttps://x402.telnyx.com/v1/audio/transcriptions?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need pay-per-use speech-to-text without a subscription, want Whisper large-v3-turbo quality, need segment-level timestamps, and are operating in a crypto-native or x402-compatible payment environment. Prefer it over OpenAI's own Whisper API when you want USDC micropayment billing or are already integrated with Telnyx infrastructure.
Side effects
- Audio file exceeds 5-minute or 12 MB limit — request rejected
- Unsupported audio format (only WAV and MP3 accepted)
- Payment failure or insufficient USDC balance via x402 — 402 response returned
- Invalid model alias — validation error
- Language hint not recognized as valid ISO-639-1 code
- Network timeout for large files close to the size limit
- word-level timestamp_granularities requested — not supported by this endpoint (segment-level only)
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| file | string | Audio file (multipart part named "file"): wav or mp3, ≤5 minutes, ≤12 MB. |
| model | string | All aliases run openai/whisper-large-v3-turbo. |
| prompt | string | |
| language | string | Optional ISO-639-1 hint. |
| temperature | number | |
| response_format | string | |
| timestamp_granularities | array | Segment-level only (upstream does not support word). |
Output
Schema · Response
{
"type": "json",
"example": {
"text": "Hello from the x402 gateway.",
"duration": 4.05,
"segments": [
{
"id": 0,
"end": 4,
"text": "Hello from the x402 gateway.",
"start": 0
}
]
}
}Tags
x402
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