# Large-recipient postcodes in forms

> What large-recipient (stormodtager) postcodes are, how the API shows them in /postnumre, on addresses and in autocomplete, and how your form handles them.
>
> https://danadresse.dk/en/guides/stormodtagere · verified 2026-11-02

Some large companies and public authorities have a postcode of their own. Mail to them is sorted straight to the recipient instead of to a postal district. This is called a large-recipient postcode (stormodtagerpostnummer), e.g. `1092 København K` for Danske Bank at Holmens Kanal 2. It appears on invoices and letters from such organisations, which is why it turns up in B2B forms, billing addresses and CRM data.

A large-recipient postcode points to an organisation's mail handling. The building still has its normal, geographic postcode: Holmens Kanal 2 is in `1060 København K`.

## What the API returns

The API follows DAWA:

| Where                                                             | What you get                                                                                             |
| ----------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------- |
| `GET /postnumre`                                                  | Geographic postcodes only, as in DAWA                                                                    |
| `GET /postnumre?stormodtagere=true`                               | The large-recipient postcodes as well                                                                    |
| `GET /postnumre/{nr}`                                             | Works for every postcode, large-recipient numbers included                                               |
| `stormodtager` on a postcode                                      | `true` for a large-recipient postcode, otherwise `false`                                                 |
| `stormodtageradresser` on a postcode                              | The access addresses that receive mail on the number, as `[{href, id}]`. `null` for geographic postcodes |
| `stormodtagerpostnummer` on `/adgangsadresser`                    | `{href, nr, navn}` for an entrance with a large-recipient postcode, otherwise `null`                     |
| `stormodtagerpostnr` and `stormodtagerpostnrnavn` in autocomplete | Filled in on suggestions for an address with a large-recipient postcode                                  |
| Autocomplete with `stormodtagerpostnumre=true`                    | Such an address is suggested twice: with the geographic postcode and with the large-recipient postcode   |

## Check a postcode

`GET /postnumre/{nr}` answers `200` for a known postcode and tells you whether it is a large-recipient postcode:

```bash id=postnr-curl run=live expect="stormodtager"
curl -s "https://api.danadresse.dk/postnumre/1092" \
  -H "X-Api-Key: $DANADRESSE_API_KEY"
```

```json id=postnr-svar run=no
{
  "href": "https://api.danadresse.dk/postnumre/1092",
  "nr": "1092",
  "navn": "København K",
  "stormodtageradresser": [
    {
      "href": "https://api.danadresse.dk/adgangsadresser/0a3f507a-8f2e-32b8-e044-0003ba298018",
      "id": "0a3f507a-8f2e-32b8-e044-0003ba298018"
    },
    {
      "href": "https://api.danadresse.dk/adgangsadresser/0a3f507a-8f34-32b8-e044-0003ba298018",
      "id": "0a3f507a-8f34-32b8-e044-0003ba298018"
    }
  ],
  "stormodtager": true,
  "kommuner": [
    {
      "href": "https://api.danadresse.dk/kommuner/0101",
      "kode": "0101",
      "navn": "København"
    }
  ]
}
```

A `404` means the number is not a postcode in the register. It is typically a typo or a retired number.

## How to handle it in the form

The purpose of the form decides what you do:

| Form                                               | Recommendation                                                                                                                                                                 |
| -------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| Delivery address for parcels, visits, installation | Require a physical address with the geographic postcode. Use autocomplete and [datavask](/en/guides/datavask-i-checkout). A large-recipient postcode is not a delivery address |
| Billing or postal address for businesses           | Accept a large-recipient postcode. It is a valid postcode for letters                                                                                                          |
| CRM data import                                    | Flag rows with an unknown postcode for manual review instead of deleting them. Rows with a large-recipient postcode are valid postal addresses                                 |

Here is a small check in Node that tells "geographic", "large recipient", "unknown" and "invalid format" apart:

```js id=postnr-node run=live expect="Hellerup"
async function tjekPostnr(nr) {
  if (!/^\d{4}$/.test(nr))
    return { status: "invalid", text: "The postcode must be four digits" };
  const res = await fetch(`https://api.danadresse.dk/postnumre/${nr}`, {
    headers: { "X-Api-Key": process.env.DANADRESSE_API_KEY },
    signal: AbortSignal.timeout(5000),
  });
  if (res.status === 404)
    return { status: "unknown", text: `${nr} is not a known postcode` };
  if (!res.ok)
    return {
      status: "could not check",
      text: "Could not check the postcode right now",
    };
  const p = await res.json();
  if (p.stormodtager) {
    return {
      status: "large recipient",
      text: `${p.nr} ${p.navn} is a company postcode. Use it for mail, not for delivery.`,
    };
  }
  return { status: "geographic", text: `${p.nr} ${p.navn}` };
}

for (const nr of ["2900", "1092", "9999", "29OO"]) {
  console.log(nr, JSON.stringify(await tjekPostnr(nr)));
}
```

You can also fetch the full list with `GET /postnumre?stormodtagere=true` once a day and check locally instead of calling the API on every keystroke. The `stormodtager` field tells you which numbers are for mail only. See [Postcodes and municipalities for dropdowns](/en/guides/postnumre-og-kommuner).

## Store the raw input

When you accept a postcode the API does not know, store it exactly as the customer typed it and flag the row, e.g. with `postnr_valideret = false`. Then you can find the rows again if you want to check them later. Store a large-recipient postcode on a billing address as it is. Do not overwrite it with the geographic postcode from datavask.

## Edge cases

- **Datavask uses the geographic postcode.** "Holmens Kanal 2, 1092 København K" gives category C, because the postcode differs from the building's (`forskelle.postnr`). The candidate is the right building with `1060`. The field `anvendtstormodtagerpostnummer` is `null`.
- **Autocomplete finds the building.** The suggestion shows the geographic postcode and carries the large-recipient postcode in `data.stormodtagerpostnr`. To offer both variants, add `stormodtagerpostnumre=true`.
- **Postcodes with a leading zero.** Every geographic postcode has four digits from 1000 upwards. Numbers below 1000, such as `0800 Høje Taastrup` and `0999 København C`, are large-recipient postcodes. The API always returns postcodes with four digits, so store them as text so the zero does not disappear.
- **Municipality from postcode.** `kommuner` on a large-recipient postcode lists the municipalities of its large-recipient addresses. To know the municipality of a specific customer, use the address.

## Next steps

- [Postcodes and municipalities for dropdowns](/en/guides/postnumre-og-kommuner)
- [Validate the address at checkout with datavask](/en/guides/datavask-i-checkout)