DUO open education data

Base URL

https://onderwijsdata.duo.nl/api/3/action

Endpoints 8

• GET/package_listNames of all 56 datasets (e.g. adressen_bo, 03_voex-v1, historische-leerlingenaantallen-po).
• GET/package_search?q=…&fq=…&rows=…Search the catalogue; rows=0 returns the count only. Also returns each dataset's resources (files) with id, format and datastore_active.
• GET/package_show?id={naam}One dataset: description, licence, metadata_modified and the resources with their resource_id and download URL.
• GET/resource_show?id={resource_id}One file: name, format, last_modified, download URL.
• GET/group_listThe eight topic groups (basisonderwijs, voorgezet-onderwijs, hoger-onderwijs, inburgering …).
• GET/group_show?id={groep}One group with title and description.
• GET/datastore_search?resource_id={id}The rows of one table, with filters, full-text search, sorting, column choice and paging. The response also lists the columns with their type.
• GET/dataset/{dataset-id}/resource/{resource_id}/download/{bestand}.csvThe whole file as CSV (path without /api/3/action, on https://onderwijsdata.duo.nl).

Filtering tested

No query language: equality filters as JSON in filters (value or list of values), plus full-text search with q. No greater-than or less-than; datastore_search_sql is disabled.

Parameters 10

Fields in the datastore (selection: school advice and primary school addresses) 8

Limits and pitfalls

• No key and no documented rate limit. Default 100 rows per call; a limit of 40,000 was served. Page with offset or _links.next. tested
• Only some CKAN actions are open (package_list, package_search, package_show, resource_show, group_list, group_show, datastore_search). tested
• Other CKAN actions (status_show, organization_list, tag_list, datastore_info, help_show) return HTTP 200 with the website's HTML, not a JSON error. Always check that the response is JSON. datastore_search_sql returns 400 "Action name not known". tested
• distinct=true counts correctly (total 15 years in the school advice table) but returned only one row. For unique values, prefer a small column selection with a high limit. tested
• Privacy: counts of 1 to 4 appear as -1 in the API (as <5 in some files). Don't add them up as numbers. tested
• Nine download URLs in the catalogue point to an internal host (beheer-ggm-ckan-prd.apps.prd.duo.rijksapps.nl) that doesn't resolve outside DUO; replace the host with onderwijsdata.duo.nl. tested
• Pupil files only have BRIN and branch code; name, address and municipality come from the address files (adressen_bo, adressen_vo …). Municipality number has no GM prefix: add GM and leading zeros to join with CBS. experience
• Resource ids don't change with a new delivery; the dataset's metadata_modified and the resource's last_modified give freshness (addresses are refreshed daily). experience

Try it HTTP 200 · 694 ms · 16 Oct

https://onderwijsdata.duo.nl/api/3/action/datastore_search?resource_id=454c5dd4-6815-4b52-ae2f-b9eebc6afa6d&filters={"PEILJAAR"%3A2024}&sort=AANTAL_LEERLINGEN desc&limit=3

{
  "help": "https://onderwijsdata.duo.nl/api/3/action/help_show?name=datastore_search",
  "success": true,
  "result": {
    "filters": {
      "PEILJAAR": 2024
    },
    "include_total": true,
    "limit": 3,
    "records_format": "objects",
    "resource_id": "454c5dd4-6815-4b52-ae2f-b9eebc6afa6d",
    "sort": "AANTAL_LEERLINGEN desc",
    "total_estimation_threshold": null,
    "records": [
      {
        "_id": 104633,
        "INSTELLINGSCODE": "05VX",
        "VESTIGINGSCODE": "00",
        "TYPE_PO": "BO",
        "PEILJAAR": 2024,
        "ADVIES": 12,
        "AANTAL_LEERLINGEN": 234
      },
      {
        "_id": 492855,
        "INSTELLINGSCODE": "17ON",
        "VESTIGINGSCODE": "00",
        "TYPE_PO": "BO",
        "PEILJAAR": 2024,
        "ADVIES": 12,
        "AANTAL_LEERLINGEN": 78
      }
    ],
    "fields": [
      {
        "id": "_id",
        "type": "int"
      },
      {
        "id": "INSTELLINGSCODE",

Shortened response, saved at harvest time. Click the URL for the real, current response.