Koopsom API

get

Returns a list of reference objects and their transaction prices.

Authorizations

BearerAuth

AuthorizationstringRequired

Bearer authentication header of the form Bearer <token>.

Query parameters

postalCodestringRequired

Postal code

Example: 1251NJ

houseNumberintegerRequired

House number

Example: 22

houseLetterstringOptional

House letter

houseNumberExtstringOptional

House number extension

valuationDatestring · dateOptional

Valuation date

Default: 2026-06-08Example: 2026-06-08

dateTransportstring · dateOptional

The acceptance date is the date on which you, as a buyer, become the owner of the house.

Responses

200

TransactionFinderResponse

application/json

idstring · nullableOptionalExample: string

statusstringRequiredExample: success

400

HTTP 400

application/json

401

HTTP 401

application/json

403

HTTP 403

application/json

404

HTTP 404

application/json

500

HTTP 500

application/json

get

/mx-transaction-finder

HTTPcURLJavaScriptPython

GET /v1/mx-transaction-finder?postalCode=1251NJ&houseNumber=22 HTTP/1.1
Host: api.matrixian.com
Authorization: Bearer YOUR_SECRET_TOKEN
Accept: */*

{
  "id": "string",
  "params": {
    "postalCode": "1251NJ",
    "houseNumber": 22,
    "houseLetter": null,
    "houseNumberExt": null,
    "valuationDate": "2026-06-08",
    "dateTransport": "2026-06-17"
  },
  "data": {
    "postalCode": "1251NJ",
    "houseNumber": 22,
    "houseLetter": null,
    "houseNumberExt": null,
    "saleDate": "2026-06-08",
    "transportDate": "2026-06-08",
    "transactionDate": "2026-06-08",
    "transactionPrice": 1,
    "transactionPriceIndexed": 1,
    "transactionPriceIndexedDateTransport": 1,
    "transactionPriceIndexedDateSale": 1,
    "valuationDate": "2026-06-08"
  },
  "error": {},
  "meta": {},
  "status": "success"
}