specification: API Commons Rate Limits
specificationVersion: '0.1'
schema: https://raw.githubusercontent.com/api-evangelist/interface-research/main/schema/api-commons.yml#/$defs/RateLimits
provider: AISStream
providerId: aisstream
created: '2026-07-12'
modified: '2026-07-12'
reconciled: false
tags:
- Vessel Tracking
- AIS
- WebSocket
- Streaming
- Rate Limiting
- Fair Use
description: >-
  AISStream.io does not publish numeric request quotas; it is a free WebSocket
  stream governed by fair use. Instead of an RPM/quota model, throughput is
  bounded by the subscription itself: a client must send a subscription message
  within 3 seconds of connecting or the socket is closed, and the volume of
  streamed messages is constrained by the declared BoundingBoxes and optional
  FiltersShipMMSI / FilterMessageTypes. Excessively broad or abusive use may
  have the connection or API key throttled or closed.
notes: >-
  No published per-minute or per-day numeric limits. Values here describe the
  documented connection behavior and fair-use constraints, not a metered quota.
sources:
- https://aisstream.io/documentation
- https://github.com/aisstream/issues
limits:
- name: Subscription Deadline
  scope: connection
  metric: seconds
  limit: 3
  notes: A subscription message must be sent within 3 seconds of opening the WebSocket or the server closes the connection.
- name: Streamed Message Volume
  scope: subscription
  metric: messages
  limit: bounded by subscription
  notes: Throughput is scoped by the declared BoundingBoxes plus optional FiltersShipMMSI and FilterMessageTypes; narrow the subscription to reduce volume.
- name: Fair Use
  scope: account
  metric: usage
  limit: fair use
  notes: No published numeric quota; abusive or excessively broad usage may be throttled or disconnected.
policies:
- name: Scope Your Subscription
  description: Use tight bounding boxes and MMSI / message-type filters to receive only the data you need.
- name: Reconnect With Backoff
  description: On disconnect, reconnect and re-send the subscription; apply exponential backoff with jitter.
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com