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: Tohoku University
providerId: tohoku
created: '2026-06-03'
modified: '2026-09-01'
reconciled: true
generated: '2026-09-01'
method: derived
x-derived-from: >-
  Corrected against live probes run 2026-09-01. The 2026-06-03 scaffold named IIIF and course-data
  APIs that do not exist on this institution's surface, and asserted a 429 throttled response that
  was never observed. Both removed.
tags:
- Education
- Higher Education
- University
- Rate Limiting
description: >-
  Tohoku University publishes no rate-limit documentation of any kind, for any surface. Probing on
  2026-09-01 found no RateLimit-*, X-RateLimit-* or Retry-After header on any successful response
  from the jMorp GraphQL endpoint or the TOUR OAI-PMH endpoint, and no throttle was triggered by
  the probe volume used. Whether a limit exists is therefore UNKNOWN, not zero and not unlimited.
  The only response header jMorp returns for correlation is x-request-id. Clients harvesting TOUR
  should behave as OAI-PMH etiquette requires — resume tokens, off-peak, modest concurrency — but
  that is convention, not a published policy of the university's.
notes: >-
  Nothing in this file is a provider claim. Every statement is either an observed absence or an
  explicit unknown.
sources:
- https://raw.githubusercontent.com/api-evangelist/tohoku/refs/heads/main/apis.yml
responseCodes:
  throttled: unknown
  note: >-
    No 429 was observed and none is documented. The jMorp GraphQL endpoint returns HTTP 200 even
    for validation failures, so a throttle there would most likely also arrive as a 200 with an
    errors[] entry rather than as a status code.
limits:
- name: Unknown
  scope: unknown
  metric: unknown
  limit: unknown
  observed_headers: []
  notes: >-
    No published limit and no rate-limit header on any probed response
    (https://jmorp.megabank.tohoku.ac.jp/api/graphql, https://tohoku.repo.nii.ac.jp/oai).
policies:
- name: Backoff Strategy
  description: Exponential backoff with jitter; honor Retry-After; harvest during off-peak hours.
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com