What a good email does.
A sourced specification for every technical detail that matters: from From: and MIME to DMARC, one-click unsubscribe, accessible HTML, and dark mode. Written for humans and agents.
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Ten parts of good email
Foundations
3 topicsMessage format, headers, MIME, identity, and the envelope.
Authentication
7 topicsSPF, DKIM, DMARC, transport security, and domain trust.
Deliverability
3 topicsReputation, list quality, bounces, and inbox placement.
Accessibility
3 topicsReadable, operable messages for people of all abilities.
Rendering
3 topicsHTML and CSS that survive real-world email clients.
Privacy
3 topicsConsent, tracking, data minimisation, and respectful measurement.
Internationalisation
3 topicsUnicode, language, direction, and international addresses.
Lifecycle
3 topicsSubscription, unsubscribe, complaints, retries, and expiry.
Security
3 topicsInjection, dangerous content, phishing resistance, and secrets.
Automation
3 topicsMachine-readable actions, calendars, receipts, and agent use.
One contract, many clients
Standards, not folklore
Every topic cites the RFC, W3C guidance, or authoritative operator documentation behind it.
Provider-agnostic
The outcome matters. Use any ESP, MTA, framework, or template system that can meet it.
Test the delivered message
Generated source is not the result. Verify what arrives after relays, filters, and clients touch it.