Data guide › Addresses

Addresses

Verified English addresses for Korean road addresses — the government's own English value, not a transliteration. Send the address in Korean or already romanised. Free — the source is published by the government with no restriction on use, and serving it costs us nothing.

What is here	Scope · Why the official value · Coverage · Known limits · In company records

Scope

What it does	Returns the verified English form of a Korean road address, plus the canonical Korean form and the postal code
What you send	The address in Korean or English — the register matches romanised input too. It must identify one address; a road name on its own does not (see limits)
Where it appears	Inside every company record and worksite as address_en, and as a standalone endpoint for addresses you bring yourself
Endpoint	GET /addresses?q=… — see the API guide. Costs 0 credits
Source	Ministry of the Interior and Safety, road-name address register

Why the official value and not a transliteration

Korean romanisation is not a character-by-character mapping. Sounds change across syllable boundaries, some road names are loanwords that keep their original spelling, and the building number comes before the road with no comma.

Korean	Official	What a rule produces
센텀동로	Centum dong-ro	Senteomdong-ro
삼성로	Samsung-ro	Samseong-ro
한록산길	Hannoksan-gil	Halloksan-gil
3공단1로	3gongdan 1-ro	3gongdan1-ro
국회대로72길 11	11 Gukhoe-daero 72-gil	11, Gukhoe-daero 72-gil

We know the size of that gap because we measured it. We wrote a rule-based converter, ran 300 addresses through it and compared each against the official register: 0% matched exactly — the comma after the building number broke every one. With the format corrected, 80% matched. The rest are the rows above, and rule-tuning does not reach them. So we return the government's value.

Coverage

What comes back	The official value, or nothing. No match → 404. More than one match → 409 with the count and up to ten candidates. This never picks for you and never approximates
How often the register resolves	We ran 120,168 distinct real Korean business addresses through it: 96.9% resolved. The 3.1% that did not were malformed at the source — a unit number written where the road name belongs, or an administrative district with no street
Freshness	Live. Every call reads the register as it stands today

Known limits

• In stored records only — the endpoint never uses it — the rule-based fallback matched the official register about 80% of the time in testing. It is used only where the register has nothing, so its real accuracy on those specific addresses is unknown — they are unresolvable for a reason, usually a malformed source address such as a unit number written where the road name belongs.
• English input works — the register matches romanised addresses as well as Korean ones, in a 20-address spot check every one matched. But it must be the official romanisation, not a guessed one. 삼성로 is Samsung-ro in the register, following the company's own spelling, where the romanisation rules would give Samseong-ro — and searching the guessed form returns nothing. Send Korean if you are not sure. Either way, a road name without a building number is ambiguous: Samseong-ro matches 5,271 addresses and seoul matches 524,919, so both return 409 rather than an arbitrary pick.
• The official register returns its own canonical Korean address, which can differ from the one you sent. address_ko in the response is what it matched, not what you asked.
• The register occasionally returns nothing for an address it does resolve. We saw one such response in a long run of calls, and the next eight attempts on the same address all succeeded. A 404 is worth retrying once before you conclude the address is unresolvable.
• The standalone endpoint calls the register live, so it reflects the register today. Values stored inside company records were resolved when the record was built.

In company records

Company records carry an address_en field that is resolved the same way, when the record is built. 97.3% of the 152,367 companies carry the official value; the rest are rendered by rule, because a record cannot be left without an address, and address_en_method says which you are looking at. The company guide has the numbers and the caveat.

Next: Companies · how to call it