specification: API Commons Rate Limits
specificationVersion: '0.1'
provider: Ordnance Survey
providerId: ordnance-survey
generated: '2026-07-26'
method: searched
created: '2026-07-26'
modified: '2026-07-26'
tags:
  - Rate Limiting
  - Geospatial
  - Open Data
description: >-
  Ordnance Survey publishes a single estate-wide rate-limiting policy. Limits
  are transactions per minute, enforced PER API and PER API PROJECT, and differ
  between live-mode and development-mode projects. Exceeding a limit returns
  429 until the rate falls back under the threshold. OS documents no
  RateLimit-* or Retry-After response headers and no per-plan quota table.
sources:
  - https://docs.os.uk/os-apis/core-concepts/rate-limiting-policy
  - https://docs.os.uk/os-apis/core-concepts/error-codes
headers:
  requestId: null
  rateLimitRemaining: null
  retryAfter: null
responseCodes:
  throttled: 429
limits:
  - name: Live-mode project
    scope: per API per project
    metric: transactions_per_minute
    limit: 600
    timeFrame: minute
    note: Each API in a live project can perform up to 600 transactions per minute.
  - name: Development-mode project
    scope: per API per project
    metric: transactions_per_minute
    limit: 50
    timeFrame: minute
    note: Each API in a development (dev) project can handle a maximum of 50 transactions per minute.
  - name: OS Places API Partner trial
    scope: per API Key across an account
    metric: transactions_per_minute
    limit: 50
    timeFrame: minute
    note: >-
      Enforced for the duration of the OS Places API Partner trial and applies
      to all projects with an OS Places API Key across an account.
guidance: >-
  "If the rate limit for an API is exceeded, subsequent requests will be
  rejected (429) until the rate falls below the allowed threshold. It's
  important to design your application to handle these errors gracefully."
gaps:
  - No documented Retry-After or RateLimit-* headers, so back-off must be blind.
  - No published concurrency limit, daily quota or burst allowance.
  - Download volume limits for OS Downloads API bulk transfers are not published.