name: AcoustID Rate Limits
description: Rate limiting policies for the AcoustID audio fingerprinting REST API. Free non-commercial use is limited to 3 requests per second. Commercial plans through acoustid.biz have no rate limiting.
url: https://acoustid.org/webservice
limits:
  - plan: Free (Non-Commercial)
    requestsPerSecond: 3
    notes: >
      Non-commercial and open source applications must not exceed 3 requests per second.
      Exceeding this limit may result in throttling or access restrictions.

  - plan: Commercial (Small / Medium / Large)
    requestsPerSecond: unlimited
    notes: >
      All paid commercial plans through acoustid.biz have no rate limiting imposed.
      Search volume is metered and billed monthly based on actual usage.

endpoints:
  - path: /v2/lookup
    method: GET
    description: Lookup audio track by fingerprint or AcoustID track ID
    rateLimit: Subject to plan limits

  - path: /v2/submit
    method: POST
    description: Submit a new audio fingerprint to the database
    rateLimit: Subject to plan limits
    notes: POST with GZip compression recommended for lengthy fingerprints

  - path: /v2/submission_status
    method: GET
    description: Check the status of a previously submitted fingerprint
    rateLimit: Subject to plan limits

  - path: /v2/track/list_by_mbid
    method: GET
    description: List AcoustIDs associated with a MusicBrainz ID
    rateLimit: Subject to plan limits

authentication:
  - type: API Key (client)
    description: Application API key obtained by registering an application at acoustid.org/new-applications. Required for all requests as the `client` parameter.
  - type: User API Key
    description: User-specific API key required for fingerprint submission. Obtained after signing in to acoustid.org.

notes:
  - Test API keys expire automatically after a few days
  - POST method with GZip compression is recommended for large fingerprints
  - All text uses UTF-8 encoding
  - Responses available in JSON (default), JSONP (with callback parameter), and XML