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System Design

The Unsubscribe Compliance

Honoring opt outs and legal rules like one click unsubscribe and suppression lists.

5 min read · core · beat Gold to climb

Why compliance matters

Notification systems must obey laws like CAN SPAM, GDPR, and carrier rules. Ignoring an unsubscribe is not just rude; it risks fines and blacklisting that hurt all your mail.

Required mechanisms

  • Marketing email must include a working unsubscribe link, often one click.
  • Opt out must be honored promptly, within the legal window.
  • A suppression list records addresses and numbers that must never be contacted again for that category.

Enforcing globally

The suppression list is checked at send time, the same place preferences are enforced, so a single opt out blocks every future attempt across all producers.

Audit trail

Regulators expect proof, so the service logs consent and opt out events with timestamps to show compliance if challenged.

Key idea

Unsubscribe compliance enforces a global suppression list and one click opt out at send time with an audit trail for regulators.

Check yourself

Answer to earn rating on the learn ladder.

1. What does a suppression list do?

2. Why check suppression at send time in the core?

3. Why keep an audit trail of consent and opt outs?