Audio Inputs

OpenRouter supports sending audio files to compatible models via the API. This guide will show you how to work with audio using our API.

Note: Audio files must be base64-encoded - direct URLs are not supported for audio content.

Audio Inputs

Requests with audio files to compatible models are available via the /api/v1/chat/completions API with the input_audio content type. Audio files must be base64-encoded and include the format specification. Note that only models with audio processing capabilities will handle these requests.

You can search for models that support audio by filtering to audio input modality on our Models page.

Sending Audio Files

Here’s how to send an audio file for processing:

1
import { OpenRouter } from '@openrouter/sdk';
2
import fs from "fs/promises";
3
4
const openRouter = new OpenRouter({
5
  apiKey: '{{API_KEY_REF}}',
6
});
7
8
async function encodeAudioToBase64(audioPath: string): Promise<string> {
9
  const audioBuffer = await fs.readFile(audioPath);
10
  return audioBuffer.toString("base64");
11
}
12
13
// Read and encode the audio file
14
const audioPath = "path/to/your/audio.wav";
15
const base64Audio = await encodeAudioToBase64(audioPath);
16
17
const result = await openRouter.chat.send({
18
  model: "{{MODEL}}",
19
  messages: [
20
    {
21
      role: "user",
22
      content: [
23
        {
24
          type: "text",
25
          text: "Please transcribe this audio file.",
26
        },
27
        {
28
          type: "input_audio",
29
          inputAudio: {
30
            data: base64Audio,
31
            format: "wav",
32
          },
33
        },
34
      ],
35
    },
36
  ],
37
  stream: false,
38
});
39
40
console.log(result);

Supported audio formats vary by provider. Common formats include:

• wav - WAV audio
• mp3 - MP3 audio
• aiff - AIFF audio
• aac - AAC audio
• ogg - OGG Vorbis audio
• flac - FLAC audio
• m4a - M4A audio
• pcm16 - PCM16 audio
• pcm24 - PCM24 audio

Note: Check your model’s documentation to confirm which audio formats it supports. Not all models support all formats.