specification: API Commons Rate Limits
specificationVersion: '0.1'
provider: MISO
providerId: miso
generated: '2026-07-27'
method: searched
created: '2026-07-27'
modified: '2026-07-27'
tags:
  - Rate Limiting
  - Energy
  - Open Data
description: >-
  MISO publishes rate limits on exactly one of its two public data surfaces. The keyed
  MISO Data Exchange gateway (apim.misoenergy.org) enforces a hard, numeric,
  per-subscription rate limit and daily quota that MISO states in its own Data Exchange
  FAQ. The anonymous Public API (public-api.misoenergy.org) carries no enforced,
  documented limit at all — MISO instead publishes a politeness request on the RT Data
  APIs page asking callers not to poll faster than once per minute. Both are recorded
  here verbatim; the second is guidance, not an enforced limit, and is marked as such.
sources:
  - url: https://help.misoenergy.org/knowledgebase/article/KA-01489/en-us
    note: MISO Data Exchange FAQs — states the 100 call/minute limit and 24,000 call/day quota.
  - url: https://www.misoenergy.org/markets-and-operations/RTDataAPIs/
    note: RT Data APIs page — the once-per-minute caching-politeness request for the anonymous Public API.
  - url: https://data-exchange.misoenergy.org/developer/products?api-version=2022-04-01-preview
    note: Portal product metadata — subscriptionRequired true, approvalRequired false, subscriptionsLimit null.
responseCodes:
  throttled: 429
  quotaExceeded: 403
headers:
  requestId: null
  rateLimitRemaining: null
  retryAfter: null
  note: >-
    MISO does not document any RateLimit-* / X-RateLimit-* response headers, and none are
    declared in either Data Exchange OpenAPI. Callers learn they are throttled from the
    status code alone.
limits:
  - name: MISO Data Exchange gateway requests
    api: miso:miso-data-exchange-pricing-api, miso:miso-data-exchange-load-generation-interchange-api
    scope: subscription
    metric: requests_per_minute
    limit: 100
    timeFrame: minute
    enforced: true
    on_exceed: HTTP 429 Too Many Requests
    quote: >-
      "There is currently a 100 call/minute rate limit and a 24,000 call/day quota."
  - name: MISO Data Exchange gateway daily quota
    api: miso:miso-data-exchange-pricing-api, miso:miso-data-exchange-load-generation-interchange-api
    scope: subscription
    metric: requests_per_day
    limit: 24000
    timeFrame: day
    enforced: true
    on_exceed: HTTP 403 Forbidden
  - name: Public API polling guidance (not enforced)
    api: miso:miso-public-api-operations-displays, miso:miso-public-api-markets-displays
    scope: caller
    metric: requests_per_minute
    limit: 1
    timeFrame: minute
    enforced: false
    on_exceed: null
    quote: >-
      "Please be respectful of caching limits and avoid accessing these links more than
      once per minute to ensure system stability and fair usage for all users."
    note: >-
      Guidance, not enforcement. Verified 2026-07-27: repeated anonymous GETs to
      public-api.misoenergy.org returned HTTP 200 with no throttling and no rate-limit
      headers.
notes: >-
  Limits apply on a per-subscription basis, so a caller with two Data Exchange product
  subscriptions (Pricing and LGI) holds two independent budgets. Page size is fixed and
  cannot be changed, so a large market day is fetched by walking pageNumber, and each page
  costs one call against both the minute limit and the daily quota.