Blog
Email Deliverability Guides & Best Practices
Guides, best practices, and intelligence from the InboxEagle team to help you land in the inbox every time.
Authentication3 min
SPF 10-Lookup Limit and SPF Flattening
SPF fails with a permerror after too many DNS lookups. Flattening can pass the check today and break when your ESP changes IP ranges.
Authentication3 min
Tracking Domains, Redirects, and URL Shorteners
Click-tracking hosts and public shorteners are a different problem from the From domain. Here is when a branded tracking domain helps, and when a redirect chain is the risk.
Authentication3 min
Unknown Senders in Your DMARC Reports
An aggregate report source you do not recognize is either a vendor you forgot or someone using your domain. Here is how to tell, without jumping to p=reject the same day.
Analytics8 min
Why Are My Emails Suddenly Going to Spam?
A sudden move to the spam folder is a diagnosis problem, not a subject-line problem. Here is how an eCommerce sender works out whether authentication, complaints, list quality, or a provider filter caused it, and how to confirm the fix.
Providers6 min
Yahoo Email Deliverability: Sender Hub and Complaint Rate
Yahoo's bulk-sender rules are authentication, a complaint rate under 0.30% on mail that reached the inbox, and one-click unsubscribe. Sender Hub is where you see your own domain. This is how to use it when Yahoo placement drops.
Authentication7 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.
Analytics11 min
Test Your Email's Spam Score Before a Klaviyo Send
How to test your email's spam score before a Klaviyo send, using data from 528,475 real campaigns on what actually correlates with inbox placement.
Gmail9 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.
E-commerce46 min
10 Best Email Deliverability Tools 2026, Tested for Ecommerce
A hands-on look at the email deliverability tool market: we tested email deliverability tools 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.
Analytics9 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.
E-commerce9 min
The Pre-Q4 Email Deliverability Audit: What to Fix Before October
A five-area audit framework for email agencies preparing Klaviyo eCommerce clients for BFCM. Authentication, reputation, list hygiene, inbox placement, and infrastructure — what to check, what bad looks like, and what to fix before it is too late.