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Spam traps


A spam trap is an email address not owned by an actual person, but monitored by inbox providers, anti-spam organizations and blacklist administrators to identify malicious senders. Although spam traps are meant to catch the bad guys, legitimate senders can also be victims due to poor data/list hygiene and questionable acquisition practices.

There are numerous types of spam traps, but the most commonly utilized records reside in the following classifications.

Pristine spam trap (honey pot)

These addresses were never used by a person, but were created solely to bait and catch malicious senders. These types of spam traps can be hidden on websites and only visible to scrapers and harvester robots. Pristine spam traps can also contain addresses as a result of a typo (i.e. or

Poor data acquisition, such as purchasing a list or not using a double opt in process, can result in sending to a pristine spam trap.

Recycled spam trap

These are email address that used to belong to real people but were converted to a spam trap after being abandoned. The amount of time it takes for an address to be considered abandoned depends on the inbox provider and can range from 90 days to over a year. Recycled spam traps can be a single email address or multiple addresses tied to a specific domain.

Poor list hygiene can result in sending to a recycled spam trap email address.

Typo domain traps

These traps are very similar to common domains, but might vary by as little as one character (i.e. instead of  They may tell a network operator that a sender is attempting to send to real users, and they may not be the strongest indicator of pure spam.  In that vein, a number of receiving entities chose not to include this type of trap in their filtering decisions, however they are still used quite extensively. Typo domain traps may also be classified as pristine spam traps by some network operators.

Result of sending to a spam trap

The result of sending to a spam trap can vary. It depends on different factors such as: the type of spam trap you hit (pristine spam traps carry more weight), how many times you hit it (even one hit can impact your reputation and deliverability) and how the spam trap operator reacts (adding your IP or domain to a blacklist).

Spam traps can extract certain metadata about the message to use for blacklisting. This metadata can include:

  • Domain and IP address identity
  • Infrastructure information such as DNS and MX records
  • Message content such as urls and digital signatures

Some possible repercussions of sending to a spam trap include:

  • Damage to your reputation: Sending to spam trap address can hurt your sending reputation and decrease inbox placement.
  • Blacklisting of the sending IP address: Being added to a blacklist database can greatly affect deliverability for your business and anyone else sharing that same IP address.
  • Domain blacklisting of a specific inbox provider: Sending to a spam trap operated by a provider such as Yahoo or Gmail could permanently blacklist your whole domain to that provider.
  • Domain blacklisting of all inbox providers: Sending to a spam trap operated by a spam operator such as Spamhaus and SpamCop can affect delivery to all inbox providers.
  • Engagement impact: Non-engaged records may lead to degradation in reputation as user behavior is a major factor in the overall sender reputation metric.

How to avoid spam traps

The best prevention of sending to spam traps is adhering to best practices of data acquisition and list hygiene.

Data acquisition best practices

How you acquire and confirm your list data greatly affects your chances of sending to a spam trap. Some best practices include:

Don’t rent or buy email lists

Purchased and rented lists often have a higher rate of spam traps due to the fact that many list providers use harvesting tools to scrape email addresses from the internet. Mailing to individuals who have not given expressed consent also increases chances of complaints which leads to poor reputation and decreased inbox placement. Sending to just one pristine spam trap can get you blacklisted, so it’s best to stay far away from purchased or rented lists.

Use double opt in and email validation

Typos and fake email addresses have the possibility of being turned into spam traps. Having an address validator on your sign up page and using double-opt in techniques can assure that an email address is valid and belongs to a real person.

List hygiene best practices

After following data acquisition best practices, you need to monitor your list on a regular basis to make sure subscriber addresses aren't turning to spam traps.

Remove hard bounced email addresses

A hard bounced email address means that the address is invalid and undeliverable.  This could be the result of a typo or an abandoned address that could be turned to a spam trap.  Removing all hard bounced address assures that you won’t be sending to these addresses. Fortunately, Cordial will automatically flag a hard bounced email as invalid and discontinue sending to that address.

Manage your inactive subscribers

Poor engagement from your subscribers can hurt your reputation and inactive email address run the risk of being turned to spam traps after a period of time. Using win back and re-engagement strategies can improve engagement, but chronic inactive subscribers should be purged from your list.

Consistent sending cadence

Sending messages with a consistent cadence will help identify inactive subscribers and generate accurate bounce reports. The less often you send, the more likely you are to have increased bounce rates. Stagnant emails lists are more likely to have spam traps as older address get turned to into traps over time.

Easy access to preference centers

Giving your subscribers an easy way to unsubscribe, change their email address and update their sending frequency and profile information will help your lists stay up to date and free of spam traps.  

Maintaining a healthy subscriber list and committing to best practices for data acquisition and list hygiene will reduce your chances of being caught by a spam trap.

While best practices apply to all senders, some engagement and cadence strategies may differ depending on the business model and subscriber base. For more information regarding deliverability strategy specific to your business, reach out to your client experience specialist.



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