SPF, DKIM & DMARC Guides
Everything you need to configure, troubleshoot, and monitor email authentication — the foundation of inbox placement.
What Is DKIM2? The Next Email Authentication Standard, Explained
DKIM2 is the IETF's overhaul of email authentication — closing replay attacks, broken forwarding, and bounce-routing gaps. What senders need to know before it ships.
What Is DMARC? Plain-English Guide for eCommerce Senders
DMARC is a setting on your domain that tells Gmail and Outlook what to do when someone sends email pretending to be you. Here's what it means, why it's now required, and how to know if yours is working.
Why Your "Mailed-By" Domain Matters for Brand Trust
82.8% of marketing emails display a third-party mailed-by domain in Gmail. Here's what that signals to your subscribers and why it's quietly costing you deliverability equity.
Setting Up a Custom Sending Domain in Klaviyo: Step by Step
A complete guide to setting up a Klaviyo custom sending domain — with DNS records, authentication verification, and why it matters for deliverability.
The Technical Anatomy of a Perfect Ecommerce Email Header
InboxEagle analyzed 256,606 emails across 16,381 brands. Only 16.7% had a perfect header. Here's what separates them from the rest — and how to fix yours.
Dedicated IP vs. Shared IP for Email: What the Data Actually Shows
InboxEagle analyzed 15,174 IPs — 7,166 dedicated and 8,008 shared. Dedicated IPs had lower spam rates but lower Primary inbox. Here's why, and when a dedicated IP for email actually makes sense.
How Domain Alignment Affects Inbox Placement in 2026
Domain alignment is why your emails fail DMARC even with valid SPF and DKIM — here's what's breaking and how to fix it.
Does DMARC Failure Guarantee the Spam Folder? A 2M Email Study
We analyzed 2.2 million emails to find out if DMARC failure sends you straight to spam. The answer is more nuanced — and more actionable — than you'd expect.
The State of Email Authentication: SPF/DKIM Adoption in Ecommerce
Email authentication adoption in ecommerce leads every other industry — yet most brands still run DMARC at p=none. Here's what the 2025/2026 data says and where the real gap is.
SPF, DKIM, and DMARC Explained: The Authentication Trinity
A plain-English breakdown of the three email authentication standards every sender needs — plus who enforces them and what comes next.