Suppression list
The addresses Sendly refuses to send to, why entries are added automatically, and why removing one is a permissioned act
Your suppression list is the set of addresses Sendly will not send to. An address on it is skipped before a message is composed, whatever asked for the send — an API call, a campaign, a workflow, or a compat endpoint.
Entries arrive from three places: an unsubscribe, a complaint, and a hard bounce. All three are automatic, and that is the point. A suppression list that depends on someone remembering to update it is a suppression list that fails on the day it matters.
Why you cannot casually clear it
Removing an address means Sendly will mail someone who previously bounced permanently, asked to stop, or reported you as spam. Each of those is a direct hit to sender reputation, and the last one may also be a legal problem depending on where the recipient lives.
So removal is treated as a consequential act rather than a convenience:
- It is a distinct API permission,
suppression:write, separate from reading the list. - For an AI agent it is one of the eight permissions that arrive unchecked on the consent screen, with the consequence spelled out. See the MCP guide.
Migrating in
Import your previous provider's unsubscribes, complaints and hard bounces before your first real send from Sendly. Sendly cannot know about a suppression that lives in another system, and the first campaign after a migration is the classic moment for mailing several thousand people who already asked you to stop.
See List hygiene.