SPF, DKIM & DMARC Guides
Everything you need to configure, troubleshoot, and monitor email authentication — the foundation of inbox placement.
Authentication6 min
SPF, DKIM, DMARC Checker: Verify All Three Records at Once
Seeing three different pass/fail screens for SPF, DKIM, and DMARC does not tell you whether your domain is actually protected. Here is what a real spf dkim dmarc checker verifies in one search, and what 591,862 real emails show about pass rates.
Authentication9 min
Gmail Emails Going to Spam? What 514K Messages Show
Your ESP dashboard says delivered. Then you check Gmail and find it in Spam. We tracked 514,492 Gmail-bound ecommerce messages between 11 June and 11 September 2026: 25% landed in spam, and unauthenticated mail was more than twice as likely to get filtered. Here's what actually moves the needle — authentication, ESP choice, and sending volume — and what a blended, all-provider dashboard hides about your Gmail-specific problem.
Authentication10 min
No DMARC Record Found? Klaviyo DMARC Setup Guide (2026)
If a checker just told you 'no DMARC record found', anyone can send email as your store and you'd never know. Unauthenticated mail hit spam 45% of the time in our data, more than double the rate for authenticated mail. 23% of the 14,101 ecommerce domains we checked this summer had the same gap. Here's why it happens to Klaviyo and Shopify stores, and the complete setup that fixes it.
Authentication39 min
10 Best Email Deliverability Tools, Tested for Ecommerce (2026)
We tested email deliverability tools hands-on across placement testing, monitoring, warmup, and authentication, then ranked them for senders on any ESP. Here's what actually works, including where our own tool falls short.
Authentication7 min
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.
Authentication9 min
What Does Email Deliverability Intelligence From 1.3M Inbox Sends Mean For Your Business
What is email deliverability intelligence? I analyzed 1.3M+ sends to show why SPF/DKIM/DMARC passes don't guarantee ecommerce inbox placement.
Authentication27 min
eCommerce Email Deliverability: The Complete Guide for Klaviyo Brands (2026)
Everything Klaviyo eCommerce brands need to know about inbox placement, sender reputation, authentication, list hygiene, and seasonal deliverability. InboxEagle data: 1 in 6 marketing emails never reaches the primary inbox.
Authentication8 min
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.
Authentication8 min
How to Set Up a Subdomain Strategy for Email Sending
Three decisions before you touch DNS: which subdomain, whether to split marketing from transactional, and how DMARC cascades. Complete setup guide.
Authentication5 min
Email Authentication for Klaviyo Senders: The Complete Guide
Email authentication is the foundation of inbox placement for every Klaviyo sender. Here's what SPF, DKIM, and DMARC actually do, why Klaviyo's default setup breaks DMARC alignment, and where to go deeper on each.
Authentication6 min
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.
Authentication8 min
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.
Authentication6 min
MTA-STS and TLS-RPT: The Email Security Standards Most Brands Miss
SPF, DKIM, and DMARC get all the attention — but MTA-STS and TLS-RPT are the two DNS records that complete your domain's email security posture. Here's what they do, why they matter, and how to set them up.
Authentication7 min
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.
Authentication11 min
12 Email Marketing Mistakes Killing Your Deliverability in 2026
Sending but not landing? These 12 email marketing mistakes — from skipped authentication to bought lists — are the most common reasons emails go to spam. Learn what to fix.
Authentication8 min
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.
Authentication5 min
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.
Authentication6 min
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.
Authentication6 min
BIMI in 2026: Google's CMC Makes Brand Logos Affordable for Everyone
Google launched a Common Mark Certificate option for BIMI in 2025 — no trademark required. Here's how BIMI works, what's changed, and whether it's worth implementing for your email program.
Authentication6 min
Microsoft Outlook's Bulk Sender Requirements: What Email Marketers Need to Know
Microsoft began enforcing bulk sender requirements for Outlook, Hotmail, and Live.com on May 5, 2025. Non-compliant mail gets a 550 5.7.515 rejection. Here's exactly what's required and how to comply.
Authentication3 min
Email Deliverability Checklist: 30 Pre-Send Checks
A complete pre-send checklist covering authentication, sender reputation, list hygiene, content, and monitoring — updated for 2026 enforcement requirements.
Authentication5 min
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.
Authentication6 min
The Complete Email Deliverability Guide for 2026
Everything you need to know about landing in the inbox — from authentication to reputation management, updated for 2026 enforcement changes.