How an address is written in Belgium
The postal format table for Belgium — the order the lines go in, the parts its operator requires, what it calls them, and the words it prints on a box — and, separately, what this server actually holds for Belgium, so the page never implies a check it cannot run.
Live demo
POST /demo/address · no key needed
Response
Look up any address to see the full API response, straight from the live service. The country decides which format it is read against.
The order the lines go in
The parts are named rather than filled in: Spaw does not know an address in Belgium and will not invent one. This block is produced by the same function that rewrites a real address, so the line order, the capitals Belgium asks for and any text its operator prints on every envelope are the checker's own behaviour rather than a second description of it.
Organisation Street name 12 Flat or unit Postal code Town or city
No recipient line: nothing in the response is about a person, so the name the envelope carries is not part of what is checked.
| field | called here | required | capitals |
|---|---|---|---|
| organization | Organisation | optional | — |
| addressLine1 | Street name | required | — |
| addressLine2 | Flat or unit | optional | — |
| locality | Town or city | required | — |
| postalCode | Postal code | required | — |
In Belgium the house number follows the street name, and that is the side it is written back on when the checker rewrites an address. The postal code is written before the town.
The postal code
A Belgium postal code is four digits.
pattern \d{4}
A national directory is installed for Belgium, so a postal code here is not only checked for shape but looked up: 1,146 codes from geonames-postal-codes, version 2026-09-17, of which 1,146 are live and 0 have been retired. A retired code is usually a real address with an out-of-date code rather than a typo, so it is scored rather than refused.
What Belgium calls an address that is not a front door
The words below are Belgium's own, taken from its postal operator's addressing guide, and they are the words the checker reads. Because they are carried, an address here with none of them answers street.
| address_type | written as |
|---|---|
| private_mailbox Private mailbox at a mail-receiving agency | PMB |
| po_box Post-office box | POSTBUS, BOITE POSTALE; BP, PB (only at the start of a line, with a number) |
| general_delivery Held at the counter for collection | POSTE RESTANTE, GENERAL DELIVERY |
| bulk_mail Business-volume arrangement | ANTWOORDNUMMER |
The anchored spellings are the conservative half of this: those words are ordinary language elsewhere in an address, so they only count when they open the line and carry a number after them.
BUS, BTE, BOITE, BOX look like box words in Belgium but name a flat or suite. They classify nothing; they only tell the parser where the unit is.
What can be checked for a Belgium address
Read from the datasets this server holds right now, not written into the page. For most countries the answer is the written form and the postcode shape and nothing beyond them — in particular not the row people assume is always there. An address can be perfectly formed and still not exist, and where no register is installed nothing here will pretend to know which.
| check | for BE | what the answer means |
|---|---|---|
| Written form | yes | The address is split into Belgium's own parts and rewritten in the order above. A missing required part is named in one typed reason rather than a general failure. |
| postal code pattern | yes | Checked against the pattern the table carries for Belgium. A value that does not match answers invalid_postal_code. |
| postal code exists | yes | 1,146 codes from geonames-postal-codes, live and terminated ones apart, so a retired code reads as retired rather than as a typo. |
| Kind of delivery point | yes | Belgium's own box naming is carried, so an address with no marker answers street rather than unknown. |
| Street exists | no | No register is installed for Belgium, so a street is neither confirmed nor denied: match_level answers null. |
| Building exists | no | No address register is installed for Belgium, so exists answers null: not evaluated, never no. Absence is not evidence here. |
| Companies at the address | no | No open company register is installed for Belgium, so companies_registered answers null and no mail-drop conclusion is drawn from a count. |
| Known mailbox branch | no | No operator branch list covers Belgium, so is_mail_drop is never set from one here. |
| Post actually arrives | no | Not from this page, and not from open data in any country: whether post is delivered, and the vacant, residential and agency flags that go with it, are the postal service's own licensed product. Those fields answer deliverability_checked: false rather than a guess. |
Null means not evaluated, never no. How to read an address-existence answer sets out what a premise, street or postcode match proves, and what absence proves.
Other countries
address-formats 2026-09-05 · address-rules 2026-09-17 · geonames-postal-codes 2026-09-17 · checked 2026-09-18
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