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Spam trap

published · September 13, 2026

A spam trap is an email address nobody uses, kept by a mailbox provider or blocklist operator so that any message sent to it proves the sender did not verify consent or clean the list.

A spam trap is an email address that no person uses, kept by a mailbox provider, an anti-abuse group or a blocklist operator so that any message sent to it proves the sender did not verify consent or clean the list. Traps are never published as traps: a pristine trap is planted on web pages for harvesters to scrape, a recycled trap is an abandoned mailbox switched back on, and a typo trap sits on a misspelled domain.

What Spaw answers

No verifier can name a trap, because a trap that is known stops working. What Spaw can see are the shapes traps take: a domain on the typo-squat map answers likely_typo, a mailbox that once said it did not exist and exists again answers recycled_mailbox, and a username that looks machine-made carries the generated weight. Reporting your bounces through the feedback endpoint feeds the not-found memory that the recycled shape is read from.

What it does not mean

A clean verification is not proof that an address is not a trap, and a trap hit is not a fine: the cost is reputation at the receivers that read the operator's list. The defence is the list itself — confirmed opt-in, prompt bounce handling, and never mailing an address nobody has heard from in years.

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markdown version: /glossary/spam-trap.md

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More glossary

  • Area-code overlay

    An area-code overlay is a new area code added over the same area as an existing one, instead of splitting it, so neighbours can hold different codes and local calls need ten digits.

  • Calling window

    A calling window is the span of local hours a sender contacts people in. Spaw answers in_call_window from the number's time zones: clock arithmetic, not compliance advice.

  • Fictional number

    A fictional number sits in a range kept out of service for films, TV and other fiction: 555-0100 to 555-0199 in North America, and ranges Ofcom, ARCEP, ACMA and ComReg reserve elsewhere.

  • International (exit) prefix

    An international prefix is what is dialled to leave a country before the calling code: 00 in most of the world, 011 in North America. Spaw reads it and suggests a fix in did_you_mean.

  • International network number

    An international network number sits under a calling code the ITU gives a global service rather than a country, such as +870, +881, +882 or +883, so its country is null.

  • Live carrier check (HLR lookup)

    A live carrier check asks the mobile networks, at the moment of the lookup, whether a number is in service, which network serves it and whether it is roaming. On Spaw it is not enabled.

  • Number pooling (thousands-blocks)

    Number pooling splits a North American central office code into ten blocks of a thousand numbers, each assigned to a carrier separately, so one code can hold several carriers' numbers.

  • Number portability

    Number portability lets a subscriber keep a phone number when changing carrier. The number's block stays listed under the carrier it was issued to, so block data names the original holder.