overlay: 1.0.0
info:
  title: API Evangelist enhancements for EIA Open Data APIv2
  version: 1.0.0
extends: openapi/eia-api-v2-openapi.yml
x-generated: '2026-07-27'
x-method: generated
x-source: https://www.eia.gov/opendata/documentation.php, https://www.eia.gov/opendata/faqs.php
x-note: |
  Non-destructive enhancements over EIA's published OpenAPI 3.0.0 (info.version 2.1.0, last
  modified 2022-12-01). Every value added here is sourced from EIA's own documentation, FAQ,
  patch notes or a live probe - nothing is invented. The original spec is never mutated.
  The gaps this overlay annotates: 272 of 278 operations carry no operationId, the api-key
  failure responses (403 API_KEY_MISSING / API_KEY_INVALID) are undeclared, error responses
  carry no schema, and the spec trails the live release (2.1.12) by ten patch versions.
actions:
- target: $.info
  update:
    x-apievangelist-slug: eia
    x-apievangelist-reviewed: '2026-07-27'
    x-live-api-version: 2.1.12
    x-live-api-version-date: '2026-03'
    x-spec-source: https://www.eia.gov/opendata/eia-api-swagger.zip
    x-spec-last-modified: '2022-12-01'
    x-changelog: https://www.eia.gov/opendata/documentation.php
    x-terms-of-service: https://www.eia.gov/opendata/register.php
    x-license-note: EIA data is provided free of charge and should be used in compliance with
      EIA's Copyrights and Reuse Policy; attribution to "EIA" or "U.S. Energy Information
      Administration" is required and the EIA logo may not be used.
- target: $.info
  update:
    contact:
      name: EIA Open Data
      url: https://www.eia.gov/opendata/
      email: developer@eia.gov
- target: $.servers
  update:
  - url: https://api.eia.gov
    description: Production - APIv2 (HTTPS only, api_key query parameter required)
- target: $.components.securitySchemes.api_key
  update:
    description: |
      Free API key, issued instantly by email from https://www.eia.gov/opendata/register.php.
      Must be supplied in the URL query string - EIA states it will NOT be read from HTTP
      headers. Missing key returns HTTP 403 API_KEY_MISSING; an invalid key returns HTTP 403
      API_KEY_INVALID. Not required for the bulk download facility at https://api.eia.gov/bulk.
    x-registration-url: https://www.eia.gov/opendata/register.php
    x-cost: free
    x-approval-required: false
- target: $
  update:
    x-rate-limits:
      sustained: ~9000 requests per hour per key
      burst: 5 requests per second per key
      published: https://www.eia.gov/opendata/faqs.php
      enforcement: automatic temporary key suspension with automatic reactivation
      headers: none
    x-pagination:
      style: offset-limit
      parameters: [offset, length]
      max_rows_json: 5000
      max_rows_xml: 300
      total_field: response.total
      truncation_warning: '{"warning":"parameter out of range","description":"The API can only
        return 5000 rows in JSON format..."}'
    x-error-envelope:
      gate: '{"error":{"code":"API_KEY_MISSING|API_KEY_INVALID","message":"..."}}'
      parameter: '{"error":"<text>","code":<int>}'
      problem_json: false
    x-idempotency: not applicable - read-only API
    x-undocumented-routes:
    - path: /v2/seriesid/{APIv1-SERIESID}
      note: Legacy APIv1 series-ID translation, documented at
        https://www.eia.gov/opendata/documentation.php but absent from this spec.
- target: $.components.parameters.data
  update:
    description: 'Columns of measured values to return, e.g. data[]=price&data[]=revenue.
      Required to receive any values - without it the response contains dimension columns only.
      Each selected column is accompanied by a <column>-units field. Valid column names come
      from the route''s own metadata.'
- target: $.components.parameters.facets
  update:
    description: 'Dimension filters, e.g. facets[stateid][]=CO&facets[sectorid][]=RES. Valid
      facet ids come from the route metadata; valid values from GET <route>/facet/{facet_id}.
      An unknown value is not an error - it returns zero rows.'
- target: $.components.parameters.frequency
  update:
    description: Periodicity to return. Valid values are declared per route in its metadata
      (e.g. hourly, daily, monthly, quarterly, annual). An invalid value returns HTTP 400 naming
      the valid frequencies.
- target: $.components.parameters.start
  update:
    description: 'Inclusive lower bound, in the route''s dateFormat. Compared lexically against
      the period stamp: for monthly data start=2008-02-01 EXCLUDES 2008-02, so use 2008-01-31.
      Since v2.1.11 identical start and end values on a lower-periodicity series return the full
      inclusive range.'
- target: $.components.parameters.end
  update:
    description: Inclusive upper bound, in the route's dateFormat.
- target: $.components.parameters.sort
  update:
    description: 'Sort array, e.g. sort[0][column]=period&sort[0][direction]=desc. Since v2.1.9
      a deterministic default sort is applied when none is supplied.'
- target: $.components.parameters.length
  update:
    description: Maximum rows to return. Hard ceiling is 5,000 in JSON and 300 in XML,
      regardless of the value supplied.
- target: $.components.parameters.offset
  update:
    description: Rows to skip before returning. Combine with length to page; response.total
      always reports the full responsive row count.
- target: $.components.schemas.DataResponse.properties.data
  update:
    description: Array of observation objects. Columns vary per route - period plus the route's
      facet columns plus each requested measure and its <measure>-units companion. Values are
      JSON strings, not numbers, since v2.1.6 (January 2024).
- target: $.components.schemas.DataResponseContainer.properties.apiVersion
  update:
    description: The live API release that served the response, e.g. "2.1.12". Pair it with the
      matching technical documentation.