Understanding spam traps

You will learn

Learn about spam traps and how to prevent sending to them, so you can protect your deliverability.

What is a spam trap?

A spam trap is an email address used to identify senders who are not following best practices or sending unsolicited email. Spam traps are commonly used to place senders in the spam folder or worse, block all traffic to a particular inbox provider, which is why in recent years, they have become more popular and are monitored by major inbox providers.

Pristine spam trap (PST)

Pristine spam traps are created with the intention of finding people who are sending spam or not following best practices. These addresses have never belonged to a real subscriber or been used to opt in to marketing emails. Sending to a PST can cause your IP to be blocklisted or your emails to go to spam. To inbox providers, this can indicate that you purchased a list, collected addresses without permission, or have other problems with how you collect email addresses.

Recycled spam trap (RST)

Recycled spam traps, unlike pristine spam traps, are addresses that were used as real addresses at some point in the past. It’s common to see RSTs as domains provided by free services, such as @yahoo or @gmail. However, in some cases, you may see domains of closed businesses being repurchased with the intention of making them RSTs.

An out-of-date email doesn’t always become an RST immediately after it falls out of use. Some inbox providers may delete an account after its owner stops signing in or using it. Receiving emails alone does not necessarily keep an account active. Once the address is deleted, if you send to the address, the email will hard bounce. Klaviyo automatically suppresses hard bounces.

The time before an address is recycled varies. An address may reject mail for 12 months or more before being reused as a spam trap. The purpose of an RST is to identify people who are not following best practices when it comes to list cleaning, not necessarily to identify spammers.

The table below summarizes provider inactivity policies. These describe mailbox closure or account deletion, not when an address becomes a spam trap. Follow each provider’s link for its current policy and exceptions.

Role accounts

Role accounts are email addresses used for a team or function, rather than an individual subscriber. They are not necessarily spam traps, but some are used to identify unsolicited mail. Avoid sending marketing emails to these group addresses or aliases, which usually have not opted in to receive them.

More details on this are outlined in RFC 2142.

How to prevent sending to spam traps

Use the following practices to reduce the risk of sending to spam traps:

• Suppress profiles that have received multiple emails but have never shown any signs of engagement. Follow How to create a never engaged segment to apply the recommended criteria, including receiving at least 5 emails in the last 180 days. Lack of engagement does not confirm that an address is a spam trap.
• Check out our guide on how to remove spam traps from your account
• Use double opt-in for new email signups so subscribers must confirm before joining the list. List imports do not trigger double opt-in.
• Never purchase a list of emails

Additional resources