# Suppression Rules and Reactivation

### How Emails/Phone Numbers Get Added to the Suppression List

There are several ways a phone number or email address can be suppressed in Bird:

**Contact-Initiated Actions:**

* Clicking an unsubscribe link in an email or SMS message
* Sending opt-out keywords like "STOP" via SMS

**System-Generated Suppressions:**

* Hard bounces due to Invalid Email indicating emails can never be delivered to an address

**Flow-based Suppressions:**

* **Create or Update Suppression** step in flows can also add to the suppression list based on any triggered automation logic.

**Manual Additions:**

* Businesses can manually add or import to the suppression list through the platform. These are called Marketer-Initiated suppression.

Learn more about creating suppressions [here](https://docs.bird.com/applications/~/revisions/83QP05Evx4ykQKDMvA32/audience/suppressions/how-to/create-a-suppression-list).

### How Emails/Phone Numbers Get Removed from Suppression List

**Flow-based Removals:**

* **Remove Suppression** step in flows can also add to the suppression list based on any triggered automation logic.

**Manual Removals:**

* Businesses can manually unsuppress a contact.

Learn more about removing suppressions [here](https://docs.bird.com/applications/~/revisions/83QP05Evx4ykQKDMvA32/audience/suppressions/how-to/unsupress-contacts).