# Tag-per-Track Musical Audio Analysis API

> Tag-per-Track Musical Audio Analysis API is a paid API for AI agents from api.tag-per-track.cloud, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).

Analyzes an audio file URL to extract BPM, musical key, mood, genres, and instruments

## Facts

- Endpoint: POST https://api.tag-per-track.cloud/api/analyze
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/tag-per-track-musical-audio-analysis-api-a6ddde4a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JYlgy6Jszy7PvvfSnrxCF

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability tag-per-track-musical-audio-analysis-api-a6ddde4a -d '<json body>'
```

Example prompt: Can you analyze this audio file and tell me its BPM, musical key, mood, genre, and what instruments are playing? Here's the URL: https://example.com/track.mp3

## When to prefer this

Choose this endpoint when you need structured musical metadata (BPM, key, mood, genre, instruments) extracted from an audio file accessible via URL. It is purpose-built for music analysis in agentic pipelines, supports common formats like MP3 and WAV, and is optimized for per-track pricing at $0.05 USDC. Prefer this over general audio transcription or speech analysis services when the input is music rather than speech.

## Known failure modes

- Audio URL is inaccessible or returns a non-200 response — analysis cannot proceed
- Unsupported audio format causes parsing failure
- Audio file is too short or contains no musical content, leading to low-confidence or empty results
- Network timeout fetching the remote audio file
- Payment not processed correctly via x402 protocol, resulting in 402 error

## How this service works

Tag-per-Track: Agentic-First Musical Audio Analysis API. Extracts BPM, Key, Mood, Genres and Instruments from audio URLs.

## Output

Returns extracted musical metadata including BPM (tempo), musical key, mood classification, genre tags, and identified instruments present in the audio track

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "fileUrl": {
   "type": "string",
   "description": "URL of the audio file to analyze (mp3, wav, etc.)"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/tag-per-track-musical-audio-analysis-api-a6ddde4a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.tag-per-track.cloud](https://www.zero.xyz/host/api.tag-per-track.cloud/llms.txt)