generated: '2026-07-27'
method: probed
source: >-
  Response headers captured live from an anonymous query against
  https://services1.arcgis.com/NKgP4VcXUzEyOnmg/arcgis/rest/services/Generation_Capacity_Layers_20250219_PUBLIC/FeatureServer/1/query,
  2026-07-27. ENMAX publishes no rate limit, quota or fair-use statement
  anywhere — these limits are signalled by the Esri ArcGIS Online platform the
  data is hosted on, and they are returned on every response.
api: enmax:enmax-power-system-capacity-arcgis-feature-services
provider_documented: false
published_by: Esri ArcGIS Online (platform), not ENMAX
signalled_in_headers: true

rate_limits:
- name: Organization request units per minute
  header: x-esri-org-request-units-per-min
  observed_value: usage=9;max=6000
  limit_count: 6000
  interval: minute
  unit: request unit
  scope: >-
    The whole ArcGIS Online organization (tenant NKgP4VcXUzEyOnmg), shared
    across every consumer of every service in it — not per API key and not per
    caller, because there are no API keys and callers are anonymous. One heavy
    third-party crawler can therefore consume headroom belonging to ENMAX's own
    public maps.
  reset: rolling one-minute window
  authenticated: false
- name: Request units charged per query
  header: x-esri-query-request-units
  observed_value: '3'
  unit: request unit
  scope: per request
  detail: >-
    The cost the individual request debited from the per-minute allowance. A
    2-row query with returnGeometry=false cost 3 units, so the 6000/min ceiling
    is a real budget rather than a nominal one for geometry-returning or
    large-page queries.

related_headers:
- header: x-esri-tiles-basic-query-mode
  observed_value: 'true'
- header: x-esri-tiles-basic-query-type
  observed_value: Basic
  note: Identifies the metering class the query was billed under.

quotas:
  published: none
  detail: >-
    No daily cap, no monthly cap, no per-IP cap and no fair-use policy is
    published by ENMAX or discoverable on the service. No 429 response was
    observed or provoked.

throttling_response:
  status_code_on_limit: not observed
  note: >-
    The limit was not deliberately exceeded. Given that every other error on
    this surface is returned as HTTP 200 with an error body (see
    errors/enmax-problem-types.yml), a client should not assume a 429 will be
    used to signal throttling.

client_guidance:
- >-
  Read x-esri-org-request-units-per-min on every response and back off as usage
  approaches max — it is the only quota feedback available.
- >-
  Use returnGeometry=false and a narrow outFields list to keep the per-request
  unit cost down.
- >-
  Respect Cache-Control public, max-age=30 and the ETag; the underlying data
  changes at most a few times a year (hosting capacity stamped February 2025,
  load capacity December 2025), so re-polling faster than that spends the shared
  budget for nothing.

caveats:
- >-
  These limits belong to the hosting tenant and can be changed by Esri or by the
  tenant administrator at any time, with no notice to consumers and no
  deprecation channel. ENMAX has made no commitment about them.