specification: API Commons Rate Limits
specificationVersion: '0.1'
provider: FERC
providerId: ferc
generated: '2026-07-27'
method: searched
created: '2026-07-27'
modified: '2026-07-27'
tags:
  - Rate Limiting
  - Open Data
  - Government
description: >-
  FERC publishes one rate limit, on the Open Data API: 1,000 requests per hour per API key, reset on
  a rolling basis, enforced by the api.data.gov API Umbrella gateway. Exceeding it temporarily blocks
  the key. Higher limits are granted by contacting support — no published tier ladder. The eForms
  XBRL API publishes no rate limit.
sources:
  - https://data.ferc.gov/developer/gettingstarted/api-key-usage/
  - https://data.ferc.gov/developer/helpandsupport/api-faqs/
headers:
  limit: X-RateLimit-Limit
  remaining: X-RateLimit-Remaining
  requestId: x-api-umbrella-request-id
responseCodes:
  throttled: 429
limits:
  - name: Open Data API requests
    api: ferc:ferc-open-data-api
    scope: api-key
    metric: requests_per_hour
    limit: 1000
    timeFrame: hour
    window: rolling
    onExceed: >-
      HTTP 429 Too Many Requests; the API key is temporarily blocked from making further requests.
    raiseLimit: contact support
notes:
  - >-
    FERC's documentation contains a typo in its own worked example — it prints "X-Ratelimit-Limit:
    1000 / X-Ratelimit-Limit: 998" where the second header is X-RateLimit-Remaining. Recorded as
    published; the header names above are the correct pair.
  - >-
    No rate limit is documented or observed on the eForms API at ecollection.ferc.gov, including its
    anonymous public read endpoints — GET /PublicSubmissionHistory returns a 10.6 MB array with no
    key and no throttle headers.