What are spam traps and how do they get onto your list?
Spam traps are addresses that exist to catch careless senders. Here are the types, how they end up on a list and how to stay clear of them.
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A spam trap is an email address that real people never use, set up by mailbox providers, anti-spam organisations and blocklist operators to identify senders with poor list practices. Mailing one tells them you are collecting addresses carelessly.
The main types
Pristine traps. Addresses created purely as bait and published where only scrapers will find them, such as hidden on a web page. Nobody ever signed up with one, so if it is on your list, the address was scraped, bought or guessed.
Recycled traps. Real addresses that were abandoned. After being unused for a long time, the provider turns them into traps. Seeing a recycled trap on your list is a sign you haven't cleaned it in a long while.
Typo traps. Domains that are common misspellings, such as a lookalike of a big provider, set up to catch addresses that were mistyped and never checked.
What happens if you hit one
It depends on the operator. Possible outcomes range from nothing, to a drop in sender reputation, to your IP or domain being listed on a blocklist. Blocklist listings can cause email to be rejected across many receiving servers until you are delisted.
How they get onto lists
- Buying, renting or scraping lists
- Old lists that haven't been mailed for a year or more
- Signup forms with no checking, where typos are accepted as typed
- Imports from old systems with no clean-up
How to stay clear
- Never buy or scrape lists. It is the most common way to meet a pristine trap, and it breaks most providers' policies.
- Verify at signup, so typos are caught while the person is still there.
- Use double opt-in, which proves a real person controls the address (opt-in guide).
- Mail regularly and retire inactive addresses (sunset policy).
- Verify old lists before re-mailing them.
Can a verifier find spam traps?
Be sceptical of anyone who says they can find all of them. Real traps are deliberately indistinguishable from normal addresses, and operators keep them secret. What verification can do is remove most of what leads to them: dead domains, typos, abandoned and disposable addresses. That reduces your exposure a lot, but it isn't a guarantee. Good list hygiene and consent are what actually protect you.
