The Ultimate Email Deliverability Checklist for 2026

Email deliverability in 2026 requires attention to an ever-expanding set of factors. This checklist consolidates essential practices for maintaining high inbox placement. Use it as a monthly audit tool to identify gaps before they affect campaign performance.

Authentication and infrastructure: verify SPF includes all authorized IPs without exceeding 10 DNS lookups. Confirm DKIM signing is enabled for all streams. Set DMARC to quarantine or reject. Verify rDNS matches your hostname. Enforce TLS 1.2 or higher. Check major blacklists.

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List health: confirm all new subscribers pass validation at signup. Hard bounce rate below 2%, soft bounce below 5%. Complaint rate below 0.05% target, never above 0.1%. Active sunset policy removing 90 to 180 day unengaged subscribers. Real-time unsubscribe processing.

Content and sending: no excessive capitalization or misleading claims. Text-to-image ratio at least 40% text. Plain-text version of every email. Consistent sending cadence with no sudden spikes above 2x daily average. New IPs warmed for 4 to 8 weeks before full volume.

Monitoring: Google Postmaster Tools, Microsoft SNDS, and Validity Sender Score configured and reviewed weekly. Monthly inbox placement testing. Quarterly full deliverability audit. Monthly DMARC report review. Alerts for blacklist detections and complaint rate spikes.