Audio

Turn speech into text, and text into speech. These routes follow the OpenAI Audio API, so client.audio.transcriptions.create and client.audio.speech.create work unchanged with the base URL https://demo-api.routerplus.com/v1.

Examples

curl https://dev2-api.routerplus.com/v1/audio/transcriptions \
  -H "Authorization: Bearer $ROUTERPLUS_API_KEY" \
  -F model=whisper-1 \
  -F response_format=srt \
  -F [email protected]

curl https://dev2-api.routerplus.com/v1/audio/speech \
  -H "Authorization: Bearer $ROUTERPLUS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "gpt-4o-mini-tts", "input": "Your order has shipped.", "voice": "coral"}' \
  --output speech.mp3

from openai import OpenAI

client = OpenAI(base_url="https://demo-api.routerplus.com/v1", api_key="tm_vk_...")

with open("meeting.mp3", "rb") as f:
    transcript = client.audio.transcriptions.create(model="gpt-4o-transcribe", file=f)
print(transcript.text)

with client.audio.speech.with_streaming_response.create(
    model="tts-1", voice="alloy", input="Your order has shipped."
) as response:
    response.stream_to_file("speech.mp3")

Send your key as Authorization: Bearer tm_vk_... or as x-api-key: tm_vk_.... A missing or invalid key returns 401.

Models

OpenAI serves all six models. GET /v1/models?output_modalities=transcription lists the transcription models, and ?output_modalities=audio lists the speech models.

POST /v1/audio/transcriptions

Request

The body is multipart/form-data. The audio file is at most 25 MiB. A larger file is a 413. RouterPlus checks every rule below before it reserves money or calls a provider. A refused request has no ledger row and no charge.

RouterPlus drops any other field and names it in the x-tm-dropped-params header. With provider.require_parameters: true, a dropped field is a 400. stream=true is a 400: the route returns one response.

Response

json:

{
  "text": "Hello there.",
  "usage": { "type": "tokens", "input_tokens": 1500, "output_tokens": 40, "total_tokens": 1540, "cost": 0.00415 }
}

whisper-1 reports the billed seconds:

{
  "text": "Hello there.",
  "usage": { "type": "duration", "seconds": 62, "cost": 0.0062 }
}

usage.cost is the charge in USD for the request. The text, srt and vtt formats do not carry it. GET /v1/generation shows it for every request.

POST /v1/audio/speech

Request

The body is JSON, at most 1 MB.

Response

The body is the audio file in response_format. RouterPlus sends each part of the audio when it arrives from the provider, so playback can start before the speech is complete.

The response does not carry the cost. GET /v1/generation shows it.

Billing

1. 01
   Before the call, RouterPlus holds an estimate of the cost on your balance.
2. 02
   After the call, it charges the billed units from the Models table and releases the rest of the hold.
3. 03
   If the provider reports no usage, RouterPlus charges the estimate it held.

The hold for each model:

A failed attempt costs nothing.

Routing and failover

RouterPlus picks the provider with the same rules as chat. Guardrails apply: a model your guardrail does not allow is a 403 with error_type: "guardrail_blocked".

If a provider fails before it answers (a 5xx, a 429 or a timeout), RouterPlus tries the next provider of the model. For speech, failover stops at the first byte of audio. After that byte, the answer comes from that provider. x-tm-attempts gives the number of attempts. x-tm-provider names the provider that answered.