---
title: "Transcribe an audio file to text."
method: POST
path: "/api/transcribe/audio"
tags: ["transcribe"]
---

# Transcribe an audio file to text.

`POST /api/transcribe/audio`

## Request

- Base URL: `https://2s.io`
- URL: `https://2s.io/api/transcribe/audio`
- Auth: API key in header `PAYMENT-SIGNATURE`

Transcribe an audio file to text. POST { url, language?, diarize? } — the audio is fetched from your URL (wav, mp3, m4a/aac, ogg/opus, flac, webm; up to 15 MB and 15 minutes per call — split longer recordings and call once per segment). Returns the full punctuated transcript, overall confidence, audio duration, detected or specified language (BCP-47, e.g. "en", "es"), word-level timestamps with confidences, and — with diarize=true — speaker-segmented utterances (who said what, when). High-accuracy speech recognition for meeting notes, podcast processing, voicemail handling, and media monitoring. Billing: payment settles before this endpoint runs (paid upstream), so an error after settlement IS charged — the error response then carries the payment receipt (PAYMENT-RESPONSE) and `X-2s-Charged: true`. upto-scheme payments settle only after success.

## Query parameters

- `trial` 1

## Request body

- object
  - `url` string, uri, required: Public audio URL. Caps: 15 MB, 15 minutes.
  - `language` string: Two-letter ISO language code.
  - `diarize` boolean: Diarize.

## Other responses

- `200` (unresolved $ref)
- `400`: Invalid request. Parameter validation (BAD_REQUEST / INVALID_PARAM with error.details.issues, MALFORMED_JSON) runs before payment and is never charged; a request-specific 400 raised by the endpoint itself runs after settlement on this paid-upstream operation and IS charged (`X-2s-Charged: true` + PAYMENT-RESPONSE receipt).
- `402`: Payment required. Body is the x402 PaymentRequirements envelope with a multi-network accepts array; the per-call price is in accepts[].amount (and on the operation as x-2s-price). Sign for whichever rail you hold USDC on (EIP-3009 for Base, partial SPL transfer for Solana) and retry with the PAYMENT-SIGNATURE header (X-PAYMENT also accepted for v1 clients). Also PAYMENT_SETTLE_FAILED (error envelope) when a verified payment failed to settle: error.details.chargeStatus is "not_charged" (retry with a fresh payment) or "unknown" (the authorization may still settle before its deadline — check it before retrying).
- `409`: Conflict — PAYER_BUSY: another upto call from this payer is still in flight. Not charged; retry after Retry-After, run upto calls from one wallet sequentially, or pay with the exact scheme.
- `429`: Too many requests — RATE_LIMITED: our per-IP / per-payer limiter. Not charged; retry after Retry-After.
- `5XX`: Server-side failure. 500 INTERNAL: unexpected error; quote error.errorId (also the X-2s-Error-Id header). 502 UPSTREAM_UNAVAILABLE (or another UPSTREAM_* code): the data provider failed — composite endpoints refuse unbilled when every source fails. 503 SERVICE_PAUSED: endpoint paused by the operator kill switch, retry after Retry-After; 503 SPEND_CAP: daily upstream budget exhausted. 504 UPSTREAM_TIMEOUT. On a paid-upstream operation (see its description) this can follow settlement: then the call WAS charged and the response carries `X-2s-Charged: true` plus the PAYMENT-RESPONSE receipt. SERVICE_PAUSED and SPEND_CAP are never charged.

---

[API](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api.md) · [All operations](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api/llms.txt) · [OpenAPI document](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api/revisions/da4c5caf686e?raw)