How do suppression lists work?

By default, the suppression list will store anyone who meets the following criteria: they unsubscribe, hard bounce, someone marks your emails as spam, or soft bounces for multiple campaigns.

To ensure these individuals are never emailed again, the email addresses in your suppression list will not be added to any of your subscribers' lists when you import a list.

How is the suppression list applied?

When you import a CSV or tab delimited file of addresses, they are first checked against the suppression list, and anyone who is on the suppression list will not be reimported. However, you can change any list to not check against the suppression list first (read on for details).

The suppression list does not prevent individuals from resubscribing themselves through a sign up form though, nor does it prevent you re-adding them via an API call.

Accessing your suppression list

Each account has their own suppression list, which you can access at any time from the Lists & Subscribers tab, pictured below:

Subscriber lists overview.

Once you access your suppression list, you can easily add and remove addresses you'd like to be included. Here's the main screen for a suppression list:

The screen where you can manage your suppression list.

If you need to import someone who is on the suppression list (and you have their explicit permission to do so) you can easily remove them from the suppression list. Simply view the list, find the email and use the checkbox to select them. Then hit the 'remove selected' button.

What is the 'suppression reason'?

Your suppression list records how somebody ends up being included on the list. Typically that would be because they unsubscribed, or bounced out, but you may also see 'suppressed', which means that they were manually added directly to the list. 'Reason unavailable' means that they were added a while ago, before reasons were recorded.

Controlling which of your lists use the suppression list

While all of your lists add any unsubscribes to the suppression list by default, you can turn this on or off on a list-by-list basis. If you'd like to ensure a particular subscriber list does not scrub any new subscribers against the suppression list, or update it with any unsubscribes, open the list and go to Unsubscribe settings in the right sidebar.

On the following page, below the heading "When someone unsubscribes from this list...", you'll see two options for how unsubscribes are handled, as shown here:

Choose what happens when someone unsubscribes from a list.

If you'd like to ensure this list never uses the suppression list, select Only unsubscribe them from this list. If do want unsubscribes to be added to the suppression list, which we recommend, select Unsubscribe them from all <Client Name> lists. You can change this setting at any time.

If you decide to change your subscriber list so that it hooks into the suppression list, you'll be given the option to make updates to both lists.

Choose which you want to make to the list now the unsubscribe process has changed.

These options allow you to instantly add anyone who previously unsubscribed from that list to the suppression list. You'll also have the option to scrub all of the active subscribers in that list against the suppression list.