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 Oxford
providerId: university-of-oxford
created: '2026-06-03'
modified: '2026-08-19'
reconciled: false
tags:
- Education
- Higher Education
- University
- Rate Limiting
description: 'The University of Oxford publishes no rate-limit table, no quota and no Retry-After header
  on any institution-operated surface, and none was observed in probing. What it does publish, uniquely
  for ORA, is an etiquette policy in prose: harvesters wanting all or a large sample of the repository
  are asked to contact the service first, and Oxford states that unexpected spidering or scraping may
  lead to access being blocked. That is a social control enforced by a human decision, not a technical
  limit a client can read. Separately, ora.ox.ac.uk sits behind Cloudflare and issues managed challenges
  (HTTP 403, cf-mitigated: challenge) to non-browser clients on some paths — bot mitigation rather than
  rate limiting, but the practical failure mode a naive client will hit first.'
notes: No 429 was observed on any surface. The throttled response code below is the protocol default,
  recorded as an expectation rather than as an observation.
sources:
- https://raw.githubusercontent.com/api-evangelist/university-of-oxford/refs/heads/main/apis.yml
responseCodes:
  throttled: 429
limits:
- name: ORA OAI-PMH
  scope: client
  metric: unspecified
  limit: none published
  notes: Oxford asks bulk harvesters to make contact first (https://ora.ox.ac.uk/api). Scheduled maintenance
    Tuesdays 07:00-09:00 UK time may return 503.
- name: ORA search / object JSON
  scope: client
  metric: unspecified
  limit: none published
  notes: Undocumented endpoint; no limit stated. robots.txt disallows /?q*, /?f*, /?page* and /export_csv_search_results,
    which is the closest thing to a stated automation boundary.
- name: Digital Bodleian IIIF
  scope: client
  metric: unspecified
  limit: none published
  notes: Image API info.json advertises maxWidth 4000 and maxHeight 4000 — a per-request size ceiling,
    not a rate limit.
- name: Oxford Text Archive OAI-PMH
  scope: client
  metric: unspecified
  limit: none published
policies:
- name: Contact before bulk harvest
  description: Oxford explicitly asks would-be bulk downloaders of ORA to get in touch so the service
    can advise on approach.
- name: Backoff Strategy
  description: No Retry-After is emitted anywhere; clients should apply exponential backoff with jitter
    on their own initiative and respect the published Tuesday maintenance window.
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
generated: '2026-08-19'
method: probed
source: Oxford's published harvesting guidance at https://ora.ox.ac.uk/api plus live probes of every surface
  in apis.yml on 2026-08-19