Email Compatibility

Write and verify HTML email that renders correctly across email clients. Use whenever building, editing, or reviewing an HTML email, an email template, or a transactional message, and whenever a question involves Outlook, Gmail, Apple Mail, or "will this render in email". Covers what CSS and HTML each client supports, backed by caniemail.com data. Provides the layout rules that keep an email compatible in the first place, then lints the finished markup and reports only what breaks, per client, with workarounds. Not for sending mail, deliverability, SPF/DKIM/DMARC, or ESP choice.