Overview

Structured headers for message classification, priority, expiration, and context that go beyond basic SMTP headers.

Problem Statement

Current email headers are: - Unstructured (Subject, custom X- headers) - No standard for metadata (priority, categories, expiration) - Client-dependent interpretation - No semantic meaning for automation

Goals

1. Standardized metadata format (JSON-LD in headers)
2. Machine-readable message classification
3. Automated workflow triggers (priority routing, auto-expiration, categorization)
4. Backward compatible display for legacy clients

Use Cases

• Priority Routing: SLA-based delivery (legal notices, alerts vs newsletters)
• Auto-Expiration: Time-sensitive messages auto-delete (2FA codes, temporary invites)
• Smart Filing: Automatic categorization (receipts, notifications, conversations)
• Workflow Integration: Trigger actions based on metadata (CRM updates, ticket creation)

Proposed Headers

X-Rich-Metadata: {
  "@context": "https://msgs.global/schema/v1",
  "@type": "Message",
  "priority": {
    "level": "high",
    "sla": "deliver-within-5min",
    "expires": "2026-03-08T00:00:00Z"
  },
  "classification": {
    "category": "financial/receipt",
    "tags": ["purchase", "invoice"],
    "sensitivity": "normal"
  },
  "automation": {
    "auto-file": "Receipts/2026/March",
    "auto-expire": "2026-04-07T00:00:00Z",
    "trigger-webhook": "https://api.example.com/process-receipt"
  },
  "thread": {
    "conversation-id": "uuid",
    "position": 3,
    "total": 5
  }
}

Integration with msgs.global

• Extend postmaster_metrics to track priority/SLA
• Auto-filing rules in webmail
• API hooks for workflow automation
• Compliance: Auto-expiration for GDPR/data retention

Status

📋 Research Phase

Next Steps

1. Define JSON-LD schema
2. Survey existing metadata standards (schema.org)
3. Build webmail UI for metadata display
4. Implement Postfix priority queuing