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: University of Macau
providerId: university-of-macau
created: '2026-06-03'
modified: '2026-09-01'
generated: '2026-09-01'
method: probed
x-operator: institution
reconciled: true
tags:
- Education
- Higher Education
- University
- Open Data
- Rate Limiting
description: >-
  The University of Macau Data and Open Data API Platform enforces limits at the Azure API
  Management gateway in front of api.data.um.edu.mo, and documents the two failure modes on its own
  Response Codes page: 403 "Quota Exceeded — out of call volume quota for your subscription within
  a given time period" and 429 "Too Many Requests — rate limit is exceeded". What it does not
  publish is the numbers. The product policy that carries the actual call-volume quota and
  rate-limit window is not readable without a UMPASS sign-in, so a developer cannot size an
  integration before subscribing. The 403 message does carry a countdown —
  "Quota will be replenished in 00:49:11" — which means the replenishment interval is discoverable
  only by exhausting it.
notes: >-
  Corrected 2026-09-01. The previous version of this file described throttling on "OAI-PMH, IIIF,
  library" endpoints; none of those exist on any um.edu.mo host and the claim was not evidenced.
sources:
- https://data.um.edu.mo/api-documents/response-codes
- https://api.data.um.edu.mo/service/media/events/all
responseCodes:
  quota_exceeded: 403
  throttled: 429
limits:
- name: Call volume quota
  scope: subscription
  metric: calls
  limit: not published
  timeFrame: not published
  notes: >-
    Enforced per Azure API Management subscription. Exhaustion returns 403 with the replenishment
    countdown embedded in the message string. No Retry-After header is documented.
- name: Rate limit
  scope: subscription
  metric: requests-per-window
  limit: not published
  notes: Exceeding it returns 429. Window length is not published.
policies:
- name: Backoff strategy
  description: >-
    Treat 403 and 429 as retryable and back off. Parse the replenishment time out of the 403
    message body, because no Retry-After header is sent. Prefer paged reads with an explicit
    pagesize over unbounded /all sweeps — pagesize is capped at 100 and defaults to 100.
- name: Pagination as a rate control
  description: >-
    Collection responses cap at 100 records. Supply count first to learn _size and _total_pages,
    then page deliberately rather than polling.
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com