Insights / Deliverability · 5 min read
Google, Yahoo and Microsoft sender rules are enforced in 2026. Authentication is table stakes, which means deliverability has quietly become a copy problem.
SPF and DKIM must both pass. DMARC must be published. One-click unsubscribe via RFC 8058. Spam complaints below 0.3 percent, bounces below 2 percent.
None of this is difficult, which is precisely the problem.
When compliance is universal, filters cannot use compliance to sort senders. They weigh recipient behaviour instead, and behaviour is downstream of whether anyone is glad to hear from you.
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