# Bop 4: compose and edit music over plain HTTP

Read this first (plain text, one fetch, every example tested):
https://bop-api.sahildev.com/bop/api/v4/guide

- Discovery, with a ready-to-fetch example song:
  https://bop-api.sahildev.com/bop/api/v4
- Compose: POST https://bop-api.sahildev.com/bop/api/v4/compose with a song.
  The reply has an immutable revision ID and a songUrl
  (https://sahildev.com/bop/studio/?revision=ID) where people hear and edit it.
- Edit: POST .../edit {"revision": ID, "batch": {"edits": [...]}}.
  Every edit makes a new revision, so branch freely.
- Inspect: POST .../inspect {"revision": ID, "inspect": {"view": "summary"}}.
- No POST? Every operation accepts GET with percent-encoded JSON, up to
  15,000 characters. Use the bop-api.sahildev.com host for long URLs.
- Sounds: https://bop-api.sahildev.com/bop/api/v4/sounds
- Schemas: https://bop-api.sahildev.com/bop/api/v4/schema
- Instrument history, with real-singer comparisons:
  https://sahildev.com/bop/instrument-review/

Revisions are public to anyone who has their ID. The API never renders audio;
the studio plays songs in the browser. Describe what you composed; hearing it
requires opening the songUrl.

The classic editor at https://sahildev.com/bop/ and its song links, API
(https://bop-api.sahildev.com/bop/api/v3) and guide
(https://sahildev.com/bop/agent-guide.txt) keep working.