---
title: "ONS CMD dataset catalogue"
method: GET
path: "/api/v1/ons/datasets"
tags: ["Statistical Agencies"]
---

# ONS CMD dataset catalogue

`GET /api/v1/ons/datasets`

Paginated list of datasets published via the ONS beta Content Management Data (CMD) API. 337 datasets as of 2026-04, including CPIH, GDP to four decimal places, labour market, retail sales index, trade, mid-year population estimates, ASHE earnings, regional GDP, weekly deaths, and Census 2021 tables. Pass `query` with a dataset id (e.g. `cpih01`) to return full metadata for that dataset instead of a page of the catalogue.

## Query parameters

- `limit` integer — Page size (max 1000).
- `offset` integer — Page offset for pagination.
- `query` string, nullable — Optional dataset id to fetch full metadata for a single dataset (e.g. 'cpih01').

## Response `200`

Page of dataset summaries or full metadata for one dataset.

- EnvelopeOnsDatasetsPayload
  - `data` OnsDatasetsPayload, required
    - `items` OnsDatasetSummary[], nullable — Page of dataset summaries when no id filter is supplied.
      - `id` string, nullable — Dataset identifier (e.g. 'cpih01', 'mid-year-pop-est').
      - `title` string, nullable — Dataset title.
      - `description` string, nullable — Dataset description.
      - `release_frequency` string, nullable — Published release cadence (e.g. 'Monthly', 'Quarterly', 'Annually').
      - `last_updated` string, nullable — Last update timestamp (ISO 8601 UTC).
      - `next_release` string, nullable — Human-readable next release string as published by ONS.
    - `count` integer, nullable — Items in this page.
    - `total_count` integer, nullable — Total datasets in the CMD catalogue.
    - `limit` integer, nullable — Page size echoed by upstream.
    - `offset` integer, nullable — Page offset echoed by upstream.
    - `id` string, nullable — Dataset id when the `query` parameter resolved to a single dataset.
    - `title` string, nullable — Dataset title for a single-dataset lookup.
    - `description` string, nullable — Dataset description for a single-dataset lookup.
    - `keywords` string[], nullable — Dataset keywords for a single-dataset lookup.
    - `last_updated` string, nullable — Dataset last update for a single-dataset lookup.
    - `release_frequency` string, nullable — Dataset release frequency for a single-dataset lookup.
    - `next_release` string, nullable — Dataset next release for a single-dataset lookup.
    - `contacts` object[], nullable — Dataset contacts for a single-dataset lookup.
    - `license` string, nullable — Dataset licence for a single-dataset lookup.
    - `links` object, nullable — Dataset links for a single-dataset lookup.
    - `national_statistic` boolean, nullable — National Statistic designation for a single-dataset lookup.
  - `meta` SugraMeta, required — Metadata attached to every /api/v1/* response envelope.
    - `endpoint` string, required — Requested endpoint path.
    - `data_time` string, required — ISO 8601 UTC timestamp of the source data, not of the request.
    - `response_time` string, required — ISO 8601 UTC timestamp when this response was produced.
    - `provider` string, required — API name and version.
    - `source` string, nullable — Identifier of the primary upstream source used for this response.
    - `attribution` string, nullable — Human-readable attribution mandated by an upstream source (e.g. a securities regulator or self-regulatory organization). Present only on responses whose source requires the owner and source to be clearly identified. Do not remove or alter it when using the response.
    - `fallback_used` boolean, nullable — True when the primary source failed and a fallback produced the data.
    - `fallback_chain` string[], nullable — Ordered list of sources attempted, in the order they were tried.
    - `cached` boolean, nullable — True when this response was served from the internal cache.
    - `stale` boolean, nullable — True when the cached response was returned after the upstream rate-limited or errored. Clients can use this to detect degraded data.

## Other responses

- `401` — Missing or invalid `x-api-key` header. JSON body with a stable `code` distinguishing `missing_api_key` (no header sent) from `invalid_api_key` (header sent, key not accepted); any other 401 source carries the generic `unauthorized` with its detail as `reason`. Plus `hint`. `plan` is always null on 401 - an unauthenticated request has no plan; quota exhaustion is 429, not 401.
- `422` — Validation Error
- `429` — Daily rate limit exceeded. Check `X-RateLimit-Reset` for the next window.
- `503` — Upstream source is temporarily unavailable. Retry after a short delay.

---

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