If you were one of the developers, researchers, or hobbyists who built on AcousticBrainz, you already know the story. The Music Technology Group at Universitat Pompeu Fabra announced the shutdown on 16 February 2022 , took the live API offline, and published the entire dataset as a one-time public dump. Four years later, there's still nothing exactly like it. This post is the honest insider's view of the post-AB landscape — written by a team that uses the frozen AcousticBrainz dump in production right now, as one of four fallback layers in our music-features API. We know what works in the dump, what doesn't, and what the realistic alternatives look like in 2026. What you actually lost AcousticBrainz had three things going for it that nothing has fully replaced: Free, public, scriptable. No API key, no rate limit, no sign-up. GET /api/v1/<mbid>/low-level returned ~120 fields per recording. Researchers could pull millions of rows for a paper without negotiating commercial terms. MBID-keyed.…