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Mail drop

published · September 10, 2026

A mail drop is an address that exists to receive post for people and companies who are not there, such as a mail-forwarding branch or a formation agent.

A mail drop is an address that exists to receive post for people and companies who are not there: a mail-forwarding branch, a virtual-office suite, a company formation agent's registered-office service.

What Spaw answers

is_mail_drop is the flag, mail_drop_provider names the operator where one is known, and mail_drop_source says which of two things decided it. operator_list means the address appears on a mail-forwarding operator's own published branch list. company_cluster means more companies name the address in an open company register than the published threshold — the signal that catches a formation agent's office with thousands of companies registered to it.

The risk score carries +50, and companies_registered carries the count itself so you can see the evidence rather than take the flag on trust.

What it is a fact about

An address. Not a person and not a company. Plenty of legitimate businesses use a formation agent's address, and one registered there has done nothing wrong; a cluster is a property of a building. company_cluster in particular is a heuristic with a threshold, and the number that produced it is published beside the flag for exactly that reason.

Related

markdown version: /glossary/mail-drop.md

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More glossary

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    An address register is a country's official file of every address its authorities recognise, usually keyed on buildings rather than letterboxes.

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  • Catch-all domain

    A catch-all domain is one whose mail server accepts mail addressed to every recipient, whether or not that mailbox exists.

  • Check digit

    A check digit is a digit computed from the rest of an identifier so that a mistyped one usually fails arithmetic before anybody looks it up.

  • Company number

    A company number is the identifier a national registrar assigns to an incorporated company, unique within that register and never within the world.

  • Credit

    A credit is the billing unit of the whole API: one credit buys one fresh lookup that produced a usable answer, on any of the six signals.

  • Datacenter IP

    A datacenter IP is an address inside a range operated by a hosting, cloud or server provider rather than by a consumer access network.