activecampaign/postmark-skills/postmark-email-best-practices

Email Best Practices

Postmark has delivered billions of transactional emails over 15+ years. This skill distills that expertise into actionable guidelines for building reliable, compliant, high-deliverability email systems.

Quick Reference

Deliverability Fundamentals

The three authentication records every sending domain must have:

With Postmark, DKIM is configured automatically when you verify a sender domain. SPF and DMARC must be set up in your DNS.

See references/deliverability.md for DNS setup, reputation factors, and domain warm-up guidance.

Transactional vs. Broadcast Email

Never mix transactional and broadcast email in the same sending stream. They have different delivery characteristics, compliance requirements, and reputation profiles.

Postmark enforces this separation with Message Streams — use outbound for transactional, broadcast for marketing.

See references/compliance.md for CAN-SPAM, GDPR, and CASL requirements.

Transactional Email Design

Good transactional emails are:

• Expected — The recipient triggered this email
• Timely — Sent immediately after the triggering event
• Actionable — One clear call to action
• Plain — Minimal design; content over decoration

Common transactional email types and their essential elements:

See references/transactional-design.md for design patterns, copy guidelines, and HTML email best practices.

List Health

Sending to invalid, inactive, or unengaged addresses is the leading cause of deliverability problems.

Key rules:

• Remove hard bounces immediately and permanently
• Suppress spam complaints immediately — never re-add
• Re-permission lists older than 12–18 months before mailing
• Never purchase or rent email lists
• Validate addresses at the point of collection

See references/list-management.md for suppression strategies, list hygiene schedules, and re-engagement workflows.

Testing Safely

Never test with real addresses at consumer providers (gmail.com, yahoo.com, etc.) — it damages sender reputation.

See references/testing.md for full testing setup and domain warm-up schedules.

Sending Reliability

Production email systems need idempotency keys, retry logic, and rate limit handling to avoid duplicate sends and silent failures.

See references/sending-reliability.md for idempotency patterns, retry strategies, and rate limit handling.

Notes

• Postmark is purpose-built for transactional email — use it for triggered 1:1 emails, not bulk marketing
• Deliverability is not just about authentication — it's about sending wanted email to engaged recipients
• A single spam complaint from a real user is more damaging than 1,000 hard bounces
• Monitor your bounce rate (keep below 2%) and spam complaint rate (keep below 0.04%)