Capture and apply the request reliably
Provide a clear unsubscribe path and process requests without sign-in when applicable rules allow it. Validate the address, record when and how the request arrived, and confirm its effective status in the sending system.
Keep suppression records separate from active membership. When importing contacts or syncing a CRM, merge opt-outs as exclusions rather than letting an older source overwrite a newer unsubscribe decision.
Verify every sending path
Check campaigns, automated workflows, transactional templates, and third-party tools that use the same audience. Each path should read current suppression status before sending and handle delayed or duplicate events consistently.
Test removal with a controlled address and confirm a later campaign excludes it. Follow requirements that apply to your region and message type, and retain only records needed to enforce and audit the preference.