Woningrisico API — the risk profile of a Dutch address, in one call

How it started

A house has a price. It also has a risk profile, and that half is scattered across a dozen government datasets, each with its own format, its own granularity and its own licence. Deltares knows about foundations. RVO knows about energy labels. KNMI knows about earthquakes. CBS knows what the neighbourhood is worth. None of them know about each other.

What it does

The Woningrisico API resolves a postcode and house number to one BAG address, and answers with the risk profile of the building it stands in: water depth at extreme rainfall, foundation risk (paalrot and differential settlement), energy label and CO2, area WOZ averages, flooding, subsidence, groundwater, heat, wildfire and earthquakes — with the nearest gas field named.

Built so the answer can be trusted

Every block carries its provenance: dataset, version, granularity, licence, attribution. And every block carries a status, because missing data is a fact too — OK, PARTIAL, NODATA, NO_ACTIVE_VERSION, UNAVAILABLE. A key is never simply absent. Refusals answer in one shape with a stable error code, and a 404 says which kind it is: address not found, address ambiguous (with the candidates listed), or building not found. Responses carry an ETag, so an integration can ask again cheaply. Every path is versioned.

Honest about what it is

These are national screening models. The API says something about a location, not about the condition of one particular building — and it says so in its own documentation rather than in the small print.