# Validate the address at checkout with datavask > Check the customer's address when the form is submitted, accept safe matches, confirm likely ones and ask for a fix on uncertain ones. > > https://danadresse.dk/en/guides/datavask-i-checkout · verified 2026-11-02 A wrong delivery address costs a returned parcel, a second shipment and an annoyed customer. Autocomplete catches most mistakes while the customer types, but not all of them: some paste the address from somewhere else, some have JavaScript turned off, and some orders arrive through an API. Server-side datavask (address washing) is the safety net that runs when the form is submitted. The endpoint is `GET /datavask/adresser` (with floor and door) or `GET /datavask/adgangsadresser` (the building entrance only). The response has the same shape as DAWA's datavask. The top-level field `kategori` is **A** for an exact match, **B** for one safe match with small spelling differences and **C** for uncertain. ## 1. Send the address The simplest is the whole address as one string in `betegnelse`: ```bash id=vask-curl run=live expect="kategori" curl -s -G "https://api.danadresse.dk/datavask/adresser" \ --data-urlencode "betegnelse=Strandvejen 100, 1., 2900 Hellerup" \ -H "X-Api-Key: $DANADRESSE_API_KEY" ``` The parser reads floor and door (`2. tv`, `st. th`, `1.mf`), lower-case house letters (`12a`), a postcode anywhere in the text and aa/å spellings (`Aabenraa`, `Kobenhavn`). Upper case and a trailing full stop (`1.`, `TV`) do not matter. If your form has separate fields, you can send them instead: `vejnavn`, `husnr`, `etage`, `dør`, `postnr` and `supplerendebynavn`. The result is the same. POST works too: `POST /datavask/adresser` with one address as a JSON body, either `{"betegnelse": "…"}` or the separate fields. Each request washes one address. To wash many addresses, see [Clean a CSV export from your CRM](/en/guides/rens-crm-csv). ## 2. Read the response The customer typed "Strandvej" instead of "Strandvejen". The wash finds exactly one address and returns B: ```json id=vask-svar run=no { "kategori": "B", "resultater": [ { "adresse": { "id": "0a3f50a4-0c39-32b8-e044-0003ba298018", "vejnavn": "Strandvejen", "adresseringsvejnavn": "Strandvejen", "husnr": "100", "supplerendebynavn": null, "postnr": "2900", "postnrnavn": "Hellerup", "status": 1, "virkningstart": "2000-02-05T19:44:20.000Z", "virkningslut": null, "adgangsadresseid": "0a3f507c-0624-32b8-e044-0003ba298018", "etage": "1", "dør": null, "href": "https://api.danadresse.dk/adresser/0a3f50a4-0c39-32b8-e044-0003ba298018" }, "aktueladresse": { "id": "0a3f50a4-0c39-32b8-e044-0003ba298018", "...": "same fields as adresse" }, "vaskeresultat": { "variant": { "vejnavn": "Strandvejen", "husnr": "100", "etage": "1", "dør": null, "supplerendebynavn": null, "postnr": "2900", "postnrnavn": "Hellerup" }, "afstand": 2, "forskelle": { "vejnavn": 2, "husnr": 0, "postnr": 0, "postnrnavn": 0, "etage": 0 }, "parsetadresse": { "vejnavn": "Strandvej", "husnr": "100", "etage": "1", "postnr": "2900", "postnrnavn": "Hellerup" }, "ukendtetokens": [], "anvendtstormodtagerpostnummer": null } } ] } ``` | Field | Use | | ----------------------------- | -------------------------------------------------------------------------------------------- | | `kategori` | A, B or C for the whole wash. This is the only category in the response | | `resultater` | The candidates, best first. With A and B there is exactly one | | `adresse.id` | The address UUID. Store it on the order | | `adresse.adgangsadresseid` | The building entrance. Store it as well | | `adresse.vejnavn` etc. | The official spelling. Use it instead of the customer's | | `aktueladresse` | The current version of the address. Differs from `adresse` if the match is a retired address | | `vaskeresultat.afstand` | Edit distance between the input and the address. 0 is exact | | `vaskeresultat.forskelle` | The distance per field, e.g. `vejnavn: 2`. Shows what the customer typed wrong | | `vaskeresultat.ukendtetokens` | Words in the input that matched nothing, e.g. `["tv"]` when the address has no door "tv" | The response has no single text field. Build the line from the fields yourself, or fetch `adressebetegnelse` with `GET /adresser/{id}`. ## 3. Decide: accept, confirm or ask Use the top-level `kategori`: | kategori | Action | | ------------------ | ------------------------------------------------------------------------------------------------------------------ | | A | Accept. Store `id` and `adgangsadresseid` | | B | Accept, but store the official text. You can show it: "We deliver to Strandvejen 100, 1., 2900 Hellerup" | | C | Show the candidates from `resultater` and let the customer choose or fix the address. Never pick one automatically | | empty `resultater` | Ask the customer to check the address. Do not necessarily block the order | Floor and door count in the category. If the customer types a floor or door that does not exist on the address, the wash returns C with the units that do exist as candidates. In Python: ```python id=vask-python run=live expect="beslutning=" import os import requests def vask(betegnelse): r = requests.get( "https://api.danadresse.dk/datavask/adresser", params={"betegnelse": betegnelse}, headers={"X-Api-Key": os.environ["DANADRESSE_API_KEY"]}, timeout=5, ) r.raise_for_status() svar = r.json() resultater = svar["resultater"] if not resultater: return "ask", [] if svar["kategori"] == "A": return "accept", resultater[:1] if svar["kategori"] == "B": return "confirm", resultater[:1] return "choose", resultater[:5] # C: let the customer choose beslutning, kandidater = vask("Strandvej 100, 1., 2900 Hellerup") print(f"beslutning={beslutning}") for k in kandidater: a = k["adresse"] print(a["id"], a["vejnavn"], a["husnr"], a["etage"], a["postnr"], k["vaskeresultat"]["forskelle"]) ``` The same logic in Node 18+: ```js id=vask-node run=live expect="beslutning=" async function vask(betegnelse) { const url = new URL("https://api.danadresse.dk/datavask/adresser"); url.searchParams.set("betegnelse", betegnelse); const res = await fetch(url, { headers: { "X-Api-Key": process.env.DANADRESSE_API_KEY }, signal: AbortSignal.timeout(5000), }); if (!res.ok) throw new Error(`HTTP ${res.status}`); const { kategori, resultater } = await res.json(); if (resultater.length === 0) return { beslutning: "ask", kandidater: [] }; if (kategori === "A") return { beslutning: "accept", kandidater: resultater.slice(0, 1) }; if (kategori === "B") return { beslutning: "confirm", kandidater: resultater.slice(0, 1) }; return { beslutning: "choose", kandidater: resultater.slice(0, 5) }; } // Rentemestervej 8 has no "2. tv": the wash returns C with the units that exist const { beslutning, kandidater } = await vask( "Rentemestervej 8, 2. tv, 2400 København NV", ); console.log(`beslutning=${beslutning}`); for (const { adresse: a } of kandidater) { console.log( `${a.vejnavn} ${a.husnr}, ${a.etage ?? "-"}. ${a["dør"] ?? ""}, ${a.postnr} ${a.postnrnavn}`, ); } ``` And in PHP with the curl extension: ```php id=vask-php run=live expect="beslutning=" $betegnelse])); curl_setopt_array($ch, [ CURLOPT_RETURNTRANSFER => true, CURLOPT_TIMEOUT => 5, CURLOPT_HTTPHEADER => ['X-Api-Key: ' . getenv('DANADRESSE_API_KEY')], ]); $svar = json_decode(curl_exec($ch), true); curl_close($ch); $res = $svar['resultater'] ?? []; if (!$res) return ['ask', []]; if ($svar['kategori'] === 'A') return ['accept', array_slice($res, 0, 1)]; if ($svar['kategori'] === 'B') return ['confirm', array_slice($res, 0, 1)]; return ['choose', array_slice($res, 0, 5)]; } [$beslutning, $kandidater] = vask('Raadhuspladsen 1, 1550 København V'); echo "beslutning=$beslutning\n"; foreach ($kandidater as $k) echo $k['adresse']['id'] . ' ' . $k['adresse']['vejnavn'] . "\n"; ``` ## 4. Store the ids on the order Once the address is accepted or confirmed, store `adresse.id` and `adresse.adgangsadresseid` alongside the text. The ids are stable UUIDs from the Danish Address Register, so you can look the address up again later or enrich it. See [Store the address id](/en/guides/gem-adresse-id). ## Edge cases - **Spelling.** "Strandvej" and "Raadhuspladsen" give B with the official name, because there is exactly one safe match. Store the official spelling, not the customer's. - **Wrong postcode.** A postcode that does not fit the street counts as a difference (`forskelle.postnr`) and gives C. Show the customer the candidates and let them fix it. - **Wrong house number.** A number that does not exist on the street gives C with nearby numbers as candidates. - **Floor and door left out.** Without floor and door the wash matches the address at entrance level if the register has one. Ask for floor and door in your form when you deliver to flats. - **New addresses.** An address created today can be missing for a short while. Let the customer continue with a flag on the order so you can check it by hand. - **Timeout or error.** Use a short timeout (3-5 seconds) and let the order through if the API does not answer. Validate it afterwards. A lost order costs more than an address that needs fixing. - **Key.** Call datavask from your server with a normal key. A browser key also works on `/datavask/adresser`, but then the customer can skip the check. ## Next steps - Help the customer before they submit: [Autocomplete widget in plain JavaScript](/en/guides/vanilla-autocomplete-widget) or the [checkout address](/checkout-adresse) page. - [Store the address id and re-validate later](/en/guides/gem-adresse-id) - [Clean a CSV export from your CRM](/en/guides/rens-crm-csv)