Blog
Email Deliverability Guides & Best Practices
Guides, best practices, and intelligence from the InboxEagle team to help you land in the inbox every time.
Authentication24 min
7 Best DMARC Checker Tools in 2026, Tested and Compared
We compared 7 DMARC checkers on record checking, report analysis, pricing, and inbox placement data.
Delivery3 min
Bounce Rate vs Complaint Rate: Which Hurts More
Bounces mean the server did not accept the mail. Complaints mean a person marked accepted mail as spam. Which one is more dangerous depends on the provider measuring it.
Authentication5 min
Changing Your Sending Domain Without Losing Reputation
A new From domain does not inherit the old one's reputation. It starts with whatever history that hostname already has, which is often none. Here is how you cut over without a week of authentication failures.
Authentication5 min
DMARC in 2026: What RFC 9989 Changes for Senders
DMARCbis is no longer a draft. RFC 9989, published May 2026, obsoletes RFC 7489. The pct tag is gone, policy discovery no longer depends on the Public Suffix List, and p=reject comes with sharper warnings. Gmail and Yahoo have not rewritten their sender requirements around the new tags.
Authentication5 min
eCommerce Email Sending Architecture
Campaigns, flows, and receipts should not be one undifferentiated stream. This is how to separate domains and reputation on purpose, and which existing guides cover the DNS once the shape is chosen.
Delivery3 min
Why Is My Email Bounce Rate Suddenly Increasing?
A sudden bounce spike is usually a new list, a provider block, or a deferral wave. Here is how to tell those apart before you suppress customers or raise volume.
Analytics4 min
Email Content Signals vs Sender Reputation
InboxEagle's Q1 2026 content studies did not show trigger words, image ratio, or link count causing spam. Complaint rate and list quality did the work. This page cites those studies and does not add a new dataset.
Delivery3 min
Email Deferrals: Why Mailbox Providers Delay Mail
A deferral is a 4xx response: the mailbox provider is telling your ESP to try again later. Here is how that differs from a bounce, a block, and the spam folder.
E-commerce3 min
Email Deliverability Postmortem Template
After the first 24 hours, write down which provider moved, what you ruled out, and how you will know the fix held. Here is a short postmortem that does not invent a recovery date.
E-commerce4 min
Email Deliverability ROI: Revenue at Risk
A delivered campaign can still miss the inbox. This is how to estimate the revenue in that gap from your own numbers, using InboxEagle's Q1 2026 placement study only as context, not as your store's loss.
E-commerce7 min
Delivered but Not Received: Why Emails Disappear
Your ESP marked the message delivered and the customer never saw it. That usually means the mailbox accepted the mail and then filed it somewhere other than the inbox, or your own platform suppressed it before the handoff. Here is how to tell those cases apart.
E-commerce6 min
How to Migrate ESPs Without Losing Deliverability
Switching email platforms does not reset domain reputation, and it can break SPF and DKIM on the day you cut over. Here is the sequence that keeps your campaigns and receipts accepted while the new platform warms up.