到達率・レンダリングガイド
受信トレイ表示、SPF/DKIM/DMARC、CSS、送信前テスト。
Why the same email looks different in every inbox
A practical guide to how Gmail, Outlook, Apple Mail, and Yahoo render HTML email differently, and what founders should expect before they blame their ESP.
ガイドを読むEmail deliverability for founders: the first 90 days
Authentication, list quality, complaint rates, and warming explained for first-time founders who need mail to reach the inbox without hiring a deliverability team.
ガイドを読むSPF, DKIM, and DMARC: setup that actually sticks
A DNS-first walkthrough of the three authentication standards mailbox providers expect, with alignment examples and a sane DMARC rollout path.
ガイドを読むEmail client CSS: what works, what fails, and what to avoid
A developer-friendly map of CSS support across Gmail, Outlook, Apple Mail, and Yahoo, with patterns that survive real inboxes.
ガイドを読むPre-send testing: a workflow that catches real failures
Litmus, seed inboxes, link checks, and spam filter tests arranged into a repeatable pre-send workflow for small teams without a QA department.
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