Send audio files to models that can transcribe, translate, or reason over speech.
Audio input lets you pass spoken audio — voice messages, call recordings, interviews, podcasts — directly to chat models that can reason over speech. The model receives the audio and responds in text, all through the standard POST /v1/chat/completions endpoint.
Audio inputs use the OpenAI-compatible input_audio content part inside a user message's content array, alongside any text parts:
{
"role": "user",
"content": [
{
"type": "input_audio",
"input_audio": {
"data": "<base64-encoded audio>",
"format": "wav"
}
},
{
"type": "text",
"text": "Transcribe this and summarize the main points in Arabic."
}
]
}Common formats: wav, mp3, ogg, flac, m4a. Audio is passed inline as base64.
Audio input is available on models with the audio_input capability. Query the catalog with ?capability=audio_input.
Use audio inputs when you want a chat model to reason over speech (summarize a call, answer questions about a recording) in the same turn as a text instruction. Use the dedicated speech-to-text endpoint when you just need a transcript.
Audio sent to a chat model is billed as part of that model's token usage (audio is tokenized by the provider). The dedicated transcription endpoint is billed per audio second instead — see the pricing reference.