Skip to content
Spaw
Get your API key

Recycled spam trap

published · September 13, 2026

A recycled spam trap is a real mailbox that was abandoned, bounced as unknown for a period, and was then reactivated by its provider to catch senders who never removed it.

A recycled spam trap is a real mailbox that its owner abandoned, that the provider then rejected as unknown for months, and that the provider switched back on purely to see who still sends to it. Nobody reads it; a message arriving there proves the sender ignored the bounces or never sent at all during the dead period, which is why recycled traps carry the most weight with the operators who keep them.

What Spaw answers

The shape is exactly what previously_invalid reports: a mailbox that answered "no such mailbox" earlier — to the handshake, or in a bounce you reported whose reason read as user unknown — and answers yes now. The date of the last not-found rides in previously_invalid_at, the verdict is risky with the reason recycled_mailbox, and the recycled_mailbox weight of 30 applies. The memory is kept for a year under a keyed hash of the address.

What it does not mean

A mailbox that revives is not always a trap: a company rehires, a person reopens an account. The signal says the address was dead and came back, and that adding it to a campaign on the strength of one fresh confirmation is exactly the mistake a recycled trap exists to catch.

Related

markdown version: /glossary/recycled-spam-trap.md

Verify addresses the same way

The Spaw API runs every check described here on each lookup, with an SMTP handshake that never sends mail. 10 free lookups a month, no card required.

Get your API key

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.