Swiss address autocomplete and validation with an API

A mistyped address is expensive: returned parcels, invoices that never arrive, duplicate customers in the CRM. In Switzerland the reference is the official directory of building addresses published by swisstopo: 3.3 million addresses, each with a federal identifier. The raw file is 470 MB and uses Swiss coordinates (LV95). Our API makes it usable in a single request.

1. Get a key

Create a free OpenData Altius account: your API key is shown in your dashboard. Each request sends it in the Authorization header.

2. Autocomplete while typing

From 3 characters, the API returns up to 10 addresses. Every word typed must appear in the street, number, postcode or locality, in any order.

curl -H "Authorization: Token YOUR_KEY" \
  "https://opendata.altius-group.ch/geodata/addresses/api/v1/addresses/autocomplete/?q=echallens 6 froideville"

{"results": [{"full_address": "Route d'Echallens 6, 1055 Froideville",
              "zip_code": "1055", "locality": "Froideville", "canton": "VD",
              "latitude": 46.6003595, "longitude": 6.6735308}]}

Call the URL from your server (so the key is not exposed in the browser) and wait 200 ms between keystrokes.

3. Validate an entered address

For a completed form, the validate call tells you whether the address exists and otherwise suggests the closest ones in the same postcode:

curl -H "Authorization: Token YOUR_KEY" \
  "https://opendata.altius-group.ch/geodata/addresses/api/v1/addresses/validate/?street=Route de Echallens&number=6&zip_code=1055"

The answer contains "valid": false and, first, the suggestion Route d'Echallens 6, 1055 Froideville. Offer the correction instead of rejecting the form.

4. What you also get

• The building ID (EGID), linking the address to the Federal Register of Buildings and Dwellings.
• GPS coordinates, for a map or a distance calculation.
• The building category (residential or not).

Quotas

The free plan allows 100 requests per day, enough to test and prototype. For a form in production, a paid plan lifts these limits. The data is updated weekly from swisstopo.

Addresses on the website · Plans and pricing