Inference

Speech to text

OpenRouter's speech-to-text API: one audio file in, its text out, never streamed. Send the audio as base64 in input_audio, or as an OpenAI multipart upload with the audio in a file part and every other field as a text part. The file is at most 25 MiB in wav, mp3, flac, ogg, webm, m4a, aac or pcm; its duration is measured before any provider is called, and a file that cannot be read is a 400, never billed. A call bills the seconds of audio. GET /api/v1/models?output_modalities=transcription lists the models your key can call, each with verbose_json.

POST/api/v1/audio/transcriptions

Your key

Request

curl -X POST https://api.llm.buzz/api/v1/audio/transcriptions \
  -H "Authorization: Bearer $LLM_BUZZ_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "openai/whisper-large-v3-turbo",
  "input_audio": {
    "data": "BASE64_AUDIO",
    "format": "mp3"
  }
}'

Response

{
  "text": "Thanks for calling.",
  "usage": {
    "seconds": 12.48,
    "cost": 0.000041558
  }
}

{
  "error": {
    "code": 400,
    "message": "...",
    "metadata": {
      "error_type": "invalid_request",
      "gateway_code": "invalid_request",
      "param": "messages"
    }
  }
}

{
  "error": {
    "code": 401,
    "message": "A valid gateway Bearer key is required. Send the virtual key as 'Authorization: Bearer <key>'.",
    "metadata": {
      "error_type": "authentication",
      "gateway_code": "invalid_key"
    }
  }
}

{
  "error": {
    "code": 402,
    "message": "...",
    "metadata": {
      "error_type": "payment_required",
      "gateway_code": "insufficient_credits"
    }
  }
}

{
  "error": {
    "code": 404,
    "message": "The requested model does not exist or is not granted to this key. GET /api/v1/models lists the model aliases available to this key.",
    "metadata": {
      "error_type": "not_found",
      "gateway_code": "model_not_found",
      "param": "model"
    }
  }
}

Authorization

An inference key, as Authorization: Bearer KEY.

Keys and limits

Body application/json

modelstringrequired
A speech-to-text model from GET /api/v1/models?output_modalities=transcription, such as openai/whisper-large-v3-turbo.
input_audioobjectrequired
data (the audio in base64) and format. A url is a 400: send the bytes.
response_formatstring
json (the default: text and usage) or verbose_json, which adds task, language, duration, segments and words, on a model whose verbose_json is true.

jsonverbose_json
languagestring
An ISO-639-1 code such as en; omitted, the provider detects it.
temperaturenumber
0 to 1.
timestamp_granularitiesstring[]
Sent with verbose_json only.
providerobject
The audio routes read only the data policy fields; order, only, ignore, allow_fallbacks and sort are accepted and ignored. With the OpenAI SDK, send it in extra_body.
Show 2 child fields
- zdrboolean
  true keeps the request on providers that declare 0 days of retention.
- data_collectionstring
  deny keeps the request on providers that declare no training and 0 days of retention.
  
  allowdeny

Response 200

The text, with usage.seconds (what the call billed) and usage.cost in US dollars. The X-Generation-Id header names the call's generation record.

Errors

400
A field is missing or malformed (invalid_request, with metadata.param), or the model cannot do what the request asks (unsupported_capability).
401
No key, or the key is unknown, expired, revoked or disabled.
402
Your balance is spent and the model is not free, or the request could cost more than your balance.
404
No model has this name, or your key may not call it.
413
The file is over 25 MiB (request_too_large). Send a shorter file.

Every error code