> ## Documentation Index
> Fetch the complete documentation index at: https://docs.harpgtm.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Suppression and unsubscribe

> Keep people and domains out of every sequence with the suppression list, and let recipients unsubscribe in one click.

## Suppression list

Open **Sequences > Suppression**. The **Suppression List** holds email addresses and domains that are never contacted, for example existing customers, partners or competitors. **Auto-Suppression Rules** can suppress hard bounces and unsubscribes automatically, and keep anyone at your own company domain out.

Harp checks the list before every send. A suppressed contact fails with `CONTACT_SUPPRESSED` and is not emailed.

Your agent can check an address with `check_suppression` and list rules with `list_suppression_rules`.

## One-click unsubscribe

Cold emails carry `List-Unsubscribe` and `List-Unsubscribe-Post` headers (RFC 8058), with a signed link for each recipient. Mail apps show these as an **Unsubscribe** button.

* Unsubscribing adds the address to the suppression list and stops that person's live sequences in the workspace.
* Opening the link shows a confirm button; only confirming unsubscribes, so link scanners can't unsubscribe anyone by accident.
* Replies don't carry the header.

## Sequences stop on their own

A reply, a bounce or an unsubscribe stops that person's sequence immediately, before anything else happens.


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