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music.openverbs.com v1 note
https://music.openverbs.com/v1/note
answers 402
Parse a note in scientific pitch notation (e.g. "A4", "C#5", "Bb3") into its letter, accidental, pitch class (0..11), octave, MIDI number and frequency in Hz (A4 = 440 Hz).
We sent a real
POST request to this endpoint and it
answered 402 with payment requirements we could parse.
- Price
- $0.002
- Network
- base
- Pay to
- 0xb3f4de103F34b99f0Da19B4F16D6B53a14C2194A
- Spec dialect
- v2 (declares x402Version 2)
- Transport
- PAYMENT-REQUIRED header
- HTTP method
- POST
- Response latency
- 302 ms
- Payment options
- 1 usable of 1
- Last checked
- 2026-09-06T01:20:09.037Z (21d ago)
- Category
- other
Re-check it yourself:
curl "https://api.the402.dev/validate?url=https%3A%2F%2Fmusic.openverbs.com%2Fv1%2Fnote"