Important: SMTP traffic declared as broadcast or auto-detected as bulk receives automatic campaign-level protections:
- Campaign Session Creation: Broadcast emails are grouped into campaign sessions for performance monitoring
- Bounce Rate Monitoring: Per-campaign bounce thresholds enforced (15% overall, 10% hard bounce)
- Auto-Pause Protection: Campaigns automatically paused if bounce rates exceed thresholds
- ISP-Specific Tracking: Monitor bounce rates per ISP (Gmail, Outlook, Yahoo, etc.)
Bulk Behavior Detection:
If you send bulk-like traffic without declaring X-Stream-Type: broadcast, the system automatically detects and protects your reputation using these signals:
- Volume patterns (high email count in short time)
- Repeated subject lines (same/similar subjects to many recipients)
- Content/template similarity (same HTML sent repeatedly)
- Marketing indicators (unsubscribe headers, tracking pixels)
- Domain concentration (many emails to same domain)
- Velocity patterns (burst sending behavior)
Enforcement Modes:
The system operates in one of four modes:
- Auto-Correct (Default): Bulk-like traffic is automatically reclassified to
broadcastand receives campaign protections - Audit: Violations logged but no enforcement applied
- Strict: Bulk-like traffic declared as
transactionalis rejected with clear error message - Permissive: No enforcement (not recommended for production)
Why This Matters:
Proper stream classification protects your sender reputation. Bulk emails sent through transactional streams can damage IP reputation and reduce deliverability for important transactional emails.