Is unsubscribe tracking legal?

Tracking who unsubscribes is not only legal but essential for compliance. You must maintain suppression lists to avoid re-emailing people who opted out. The issue isn't whether to track unsubscribes but what else you do with that data.

Legitimate unsubscribe tracking: recording email addresses or hashes, unsubscribe dates, which list they left, and source of original subscription. This supports compliance and legitimate business analysis of list churn.

Problematic practices: continuing to track behavior after unsubscribe, sharing unsubscribe data with third parties, or using unsubscribe events to trigger other marketing channels. Once someone opts out of email, respect that signal across your marketing ecosystem.