The 0507 number: why a Korean business phone might not be the business

A Korean business phone number starting 0507 is not the business's phone number. It is a relay Naver puts in front of it, and depending on the vertical between 37% and 87% of businesses publish only that.

What a 0507 number is

A safe-number prefix. Calls to it are forwarded to the business's real line, so it works for reaching them, but it is allocated by the platform rather than by the business and it can be withdrawn or reassigned independently of them.

It is not a geographic area code, which is the first practical consequence: any analysis that infers location from a phone prefix silently misplaces every business with a relay.

Why Naver puts one there

Two reasons that both make sense from Naver's side. It protects the business's real line from being harvested, and it makes calls originating from Naver measurable — a relay is an attribution channel as much as a privacy feature.

How common it is

Between 37% and 87% of businesses, depending on vertical, publish only the relay. That is a wide range, and it is wide for the same reason phone coverage itself varies by vertical: different kinds of business have different relationships with the platform.

The flag, and why it is a field

phone_is_virtual is a boolean on every row. It is a field rather than something inferred from the prefix downstream, for the same reason cache metadata belongs on the row: whatever your pipeline will need to reason about later should be recorded while it is still known.

Prefix-sniffing in the consumer also breaks quietly. Korea has other non-geographic prefixes, and a new relay range would produce silent misclassification in every downstream system at once.

What it means for outreach and analysis

• Reachability. A relay usually works, but it is a redirect — and if it is withdrawn, your contact is dead while the business is fine.
• Deduplication. Several businesses can share a relay range, so a phone number is a weaker identity key than it looks. Use place_id.
• Attribution. Calls through a relay are visible to the platform. If you are measuring your own campaign, that is a channel you do not control.
• Geography. Never infer a region from a 0507 number. Use region and the addresses.

Practical handling

SELECT
  phone_is_virtual,
  COUNT(*)                                  AS businesses,
  ROUND(100.0 * COUNT(*) / SUM(COUNT(*)) OVER (), 1) AS pct
FROM businesses
WHERE phone IS NOT NULL
GROUP BY phone_is_virtual;

Run that first on any new vertical. It takes a second and it tells you what fraction of your contact list is a redirect — which is a number you want before you build a campaign on it, not after.