Open Archives (Open Archieven)

Base URL

https://api.openarchieven.nl/1.1

Endpoints 14

• GET/records/search.jsonSearch by name (also two names with & and a year or period); filters on archive, source type, place, birthplace, role and country. Total in response.number_found.
• GET/records/show.jsonOne record in the A2A model (archive + identifier). Also as .xml, .gedcom, .ttl and .nt by changing the extension.
• GET/records/match.jsonMatch a person (name + birth year) to birth and death records.
• GET/records/getBirths.json, /getDeaths.json, /getMarriages.jsonBirth, death and marriage records by name, year and place.
• GET/stats/archives.jsonAll archives with archive_code, ISIL code, name and website.
• GET/stats/records.jsonNumber of records per archive and per source type within it (archive_code= for one archive).
• GET/stats/sources.json, /stats/events.json, /stats/comments.jsonCounts per source type, per event and comments. Returned an empty list on 16 Oct 2026.
• GET/stats/breakdown.jsonCross-tab: count per archive, source type, event, place or year (1500 to 1960) with filters. Returned HTTP 503 (error_code 52) on 16 Oct 2026.
• GET/stats/familynames.json, /stats/firstnames.json, /stats/professions.jsonMost frequent surnames, first names and occupations for a place and period.
• GET/related/weather.jsonHistorical KNMI weather on a date and location (values in tenths, with a label per field).
• GET/related/census.jsonDutch census data for a place and year.
• GET/transcriptions/search.json, /browse.json, /show.jsonFull-text search of transcribed pages, browse by archive and inventory, fetch one transcription.
• GEThttps://sparql.openarchieven.nl/{oa-a2a|oa-pico|oa-pico-recon}Three SPARQL endpoints (QLever): records (A2A), person observations in PiCo, and reconstructed persons.
• GEThttps://api.openarchieven.nl/oai-pmh/?verb=…OAI-PMH 2.0, format oai_a2a, 115 sets (one per archive), dates as YYYY-MM-DD.

Filtering from the description

Separate query parameters per endpoint (name, archive_code, sourcetype, eventplace …). For questions about relations and counts across everything: SPARQL at sparql.openarchieven.nl.

Parameters 13

Fields in the responses (selection) 11

Limits and pitfalls

• 4 requests per second per IP address (OpenAPI description); more by arrangement. from the description
• Search: max 100 per page and offset up to 10,000 (above that HTTP 400, error_code 50). For everything: OAI-PMH or the file exports. tested
• SPARQL: heavy queries (GROUP BY over all triples of oa-a2a or oa-pico) returned HTTP 502 (proxy) after 30 seconds. A LIMIT query or a query about one subject answers within a second. tested
• On 16 Oct 2026 stats/sources.json returned an empty list after 10 seconds and stats/breakdown.json HTTP 503 with error_code 52 ('Service temporarily unavailable'). stats/records.json worked and counts per archive and per source type. tested
• Errors come as JSON with error_code and error_description; the HTTP status is correct (400, 503). tested
• API version 1.1 uses archive_code; older examples with archive= do not work for search.json. from the description
• Records are not people: one person appears in many records. Reconstructed persons are in oa-pico-recon (schema:spouse, parent, children, sibling). tested
• There is also an MCP server (mcp.openarchieven.nl) and OpenSearch descriptions per language. from the description

Try it HTTP 200 · 397 ms · 16 Oct

https://api.openarchieven.nl/1.1/records/search.json?name=Huizinga&eventplace=Groningen&number_show=3&lang=nl

{
  "query": {
    "eventplace": "Groningen",
    "name": "Huizinga",
    "only_results_with_scans": false,
    "start": 0,
    "number_show": 3,
    "sort": 1,
    "language": "nl"
  },
  "response": {
    "number_found": 5891,
    "docs": [
      {
        "pid": "Person1",
        "identifier": "182dc2c2-3c73-4103-a6bf-1eedb05dc8b1",
        "archive_code": "gra",
        "archive_org": "AlleGroningers",
        "archive": "AlleGroningers",
        "personname": "A. Huizinga",
        "relationtype": "Geregistreerde",
        "_relationtype": "Geregistreerde",
        "eventtype": "Registratie",
        "_eventtype": "Registratie",
        "eventplace": [
          "Groningen"
        ],
        "sourcetype": "Inschrijving gevangene",
        "url": "https://www.openarchieven.nl/gra:182dc2c2-3c73-4103-a6bf-1eedb05dc8b1"
      },
      {
        "pid": "Person1",
        "identifier": "AA10953C-AAB1-41D9-9365-C608085BD972",
        "archive_code": "gra",
        "archive_org": "AlleGroningers",
        "archive": "AlleGroningers",
        "personname": "A. Huizinga",
        "relationtype": "Geregistreerde",
        "_relationtype": "Geregistreerde",
        "eventtype": "Registratie",

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