If you need to stop mailing specific people, or pause and filter outreach to specific recipients, LettrLabs handles both through one feature: Suppression Lists. This guide explains what Suppression Lists cover today, who has access, and how to use them responsibly as your mail volume grows.
The short version
If you're looking for "Do Not Mail," you're in the right place — Do Not Mail is now part of Suppression Lists. The old Do Not Mail page redirects here automatically.
Suppression Lists are available on the Premium plan and above. On a lower tier, visiting this feature prompts an upgrade.
What Suppression Lists do
A suppression list is a set of recipients (added directly, or matched by mail history/conversion history) that you exclude from a mailing. You can apply suppression at different scopes depending on how broad or narrow the exclusion needs to be:
Global — excludes a recipient from every mailing across your account.
Automation type — excludes a recipient from every automation of a given type (for example, every Radius Mail automation), while still allowing other automation types to reach them.
A specific automation — excludes a recipient from one particular automation only.
Order type — excludes a recipient from a category of one-off orders.
A specific order — excludes a recipient from one particular order.
Unverified: the exact labels and configuration screens for each of the five scopes above (Global/Automation type/Automation/Order type/Order) are confirmed to exist in the codebase, but the precise in-app wording and step-by-step configuration flow for each scope were not walked through on a live screen for this guide. Verify the exact click path before treating the scope names above as literal UI labels.
Building a suppression list
You can build a suppression list two ways:
Upload a list — add specific recipients directly, the same way you'd upload a mailing list elsewhere in LettrLabs.
Match by activity — build a suppression rule off recipients who were already mailed, or who already converted, so you don't re-mail someone who's already been reached or already responded.
Why this matters
Protects brand reputation and customer trust by avoiding repeat or unwanted sends.
Reduces wasted spend on recipients who shouldn't be mailed again.
Simplifies compliance and governance as your mail volume and number of automations grow.
Choosing the right scope
Use Global for a hard, permanent stop — the direct replacement for what used to be called Do Not Mail. Once a recipient is suppressed globally, they're excluded from every mailing in your account.
Use a narrower scope (automation type, a specific automation, order type, or a specific order) when you want to stop mailing someone in one context without blocking every other context — for example, suppressing someone from a specific winback campaign after they've already converted, without excluding them from an unrelated Radius Mail automation.
What's not covered without upgrading
On a plan below Premium, Suppression Lists aren't available in-app. If you need to keep a list of people to exclude, you'll need to maintain it outside LettrLabs and remove matches before uploading a recipient list manually — this only works for uploaded lists, and it does not protect automated, dynamically-generated audiences (Radius Mail, Mover Mail, Storm Automation, Lead Reveal) since those recipients are never manually uploaded in the first place.
Best practices
Decide your default scope. Most teams start with automation-type or automation-level suppression for day-to-day campaign hygiene, reserving Global suppression for explicit opt-out requests.
Capture a reason when you add someone. Note why a recipient was suppressed and at what scope, so a future review (or a customer question) has an answer.
Review suppression rules periodically. A rule built for a one-time campaign can quietly keep suppressing recipients long after that campaign ended.
Import any existing do-not-mail data before your first campaign. If you were maintaining your own exclusion list before upgrading, bring it in as a Global suppression list first.
Want help deciding which suppression scope fits your workflow? Reach out to our team — we're happy to help you set it up.