Guides · API

Dutch energy label API

Netherlands home energy label (EPC, energielabel) lookup by address: the officially registered label A++++ to G, registration and expiry date, building type and energy index, or a clear 'none registered'. For real estate, mortgage, green-finance, ESG and renovation agents. Input: postcode + house number. Source: RVO EP-Online, the Dutch national register.

0.005 USDC per call · GET /v1/energy-label · free preview at /v1/energy-label/preview

Parameters

Name	Required	Description
`postcode`	no	Dutch postcode, 4 digits + 2 letters, e.g. 3511LX
`house_number`	no	House number, e.g. 1
`house_letter`	no	Optional house letter, e.g. A
`addition`	no	Optional house number addition, e.g. 2 or BIS
`q`	no	Alternative to postcode: free-text address, e.g. 'Visschersplein 1 Utrecht'

Example request

curl "https://factline.dev/v1/energy-label?postcode=2517AS&house_number=100"
# 402 Payment Required: pay with an x402 client (USDC on Base), or send
# Authorization: Bearer <your Factline API key>

Example response

{
  "address": {
    "label": "Laan van Meerdervoort 100, 2517AS 's-Gravenhage",
    "postcode": "2517AS",
    "house_number": 100,
    "city": "'s-Gravenhage",
    "bag_object_id": "0518010001775699"
  },
  "energy_label": {
    "label": "A",
    "registered": "2020-12-31",
    "inspected": "2020-12-30",
    "valid_until": "2030-12-30",
    "simplified_label": false,
    "building_type": "Flatwoning (overig)",
    "energy_index": 1.02
  },
  "source": "RVO EP-Online"
}

Use it from an AI agent

Agents with an x402 wallet call the URL directly and pay per request. Assistants that speak MCP connect to https://factline.dev/mcp. Full reference: docs, OpenAPI, llms.txt. Businesses: API keys with a free trial.

Questions

How much does the Dutch energy label cost?

0.005 USDC per call, paid per request with x402 (no account), or included in a Factline API key plan with a free trial. Calls that fail are not charged.

Can I try it for free?

Yes: GET /v1/energy-label/preview with the same parameters validates your input and shows what the paid answer contains, at no cost.

Where does the data come from?

Official public registers and open data, named with their licence in every response (source field) and at /.well-known/x402-license-provenance.