We also have Conversations webhooks that you can subscribe to in order to lern about new Conversations threads, updates to existing Conversations threads, and new messages on threads. You can create subscriptions for these in the "Webhooks" page for your app in your developer portal, or via the Webhooks API.
The available webhook events are:
Conversation - Created (converation.creation)
Indicates that a new Conversations thread has been created
Conversation - Deleted (conversation.deletion)
Indicates that a Conversations thread has been archived (or soft-deleted)
Conversation - Deleted for privacy (conversation.privacyDeletion)
Indicates that a Conversations thead has been purged (or hard-deleted)