Audio API Guide

Lossless audio concatenation — upload MP3 or AAC files and get merged binary audio back in milliseconds. No re-encoding, no quality loss.

Base URLhttps://api.creatornode.io/audio

What is the Audio API?

The Audio API provides lossless audio processing endpoints:

Merge Fast — upload 2–20 MP3 or AAC files and get a single merged audio file back as a binary response. Lossless stream-level concatenation ensures zero quality loss and near-instant processing.

This is the first binary-response endpoint in the CreatorNode platform. Success returns raw audio data with metadata in X-Audio-* response headers. Errors return standard JSON.

🎵 Lossless Merge

Stream-copy concatenation (no re-encoding). The output is bit-identical to the input streams — zero quality loss.

⚡ Fast Processing

Merges complete in milliseconds regardless of file duration. No re-encoding, no waiting — just instant binary output.

🔇 Silence Spacing

Insert custom silence gaps between tracks. Specify per-gap durations in milliseconds for precise control.

🔑 Free Tier

20 requests/day with no API key. Merge up to 3 files per request on the free tier.

Endpoints

Click an endpoint to see the full guide — examples, tips & tricks, and limits.

POST/audio/v1/merge-fast

Merge Fast

Lossless audio file merging — concatenate MP3/AAC tracks with optional crossfade.

Credit Costs

🎵Audio APILossless audio merging

Endpoint	Cost	Description
`/audio/v1/merge-fast`	2+ credits	Merge 2–20 audio files losslessly. Base cost covers first 50 MB, +1 credit per additional 50 MB block (max 5 credits).	Full guide →

See the Pricing page for credit packages and tier comparison.

Usage Example

Merge two MP3 files

Upload audio files as multipart form data and receive merged binary audio:

// Node.js example
const fs = require('fs');

const form = new FormData();
form.append('files', new Blob([fs.readFileSync('intro.mp3')]), 'intro.mp3');
form.append('files', new Blob([fs.readFileSync('outro.mp3')]), 'outro.mp3');
form.append('metadata', JSON.stringify({ format: 'auto' }));

const response = await fetch('https://api.creatornode.io/audio/v1/merge-fast', {
  method: 'POST',
  headers: { 'X-API-Key': process.env.CREATORNODE_KEY },
  body: form,
});

// Success: Content-Type is audio/mpeg or audio/aac (binary body)
// Error: Content-Type is application/json (standard error body)
if (response.headers.get('content-type')?.startsWith('audio/')) {
  const merged = Buffer.from(await response.arrayBuffer());
  fs.writeFileSync('merged.mp3', merged);

  console.log('Format:', response.headers.get('x-audio-format'));
  console.log('Duration:', response.headers.get('x-audio-duration-ms'), 'ms');
  console.log('Files merged:', response.headers.get('x-audio-file-count'));
} else {
  const error = await response.json();
  console.error(error.error.code, error.error.message);
}