Blog
Email Deliverability Guides & Best Practices
Guides, best practices, and intelligence from the InboxEagle team to help you land in the inbox every time.
E-commerce10 min
How to Monitor Your Email Deliverability in Real Time
A practical guide to email deliverability monitoring in real time — the signals that matter, the tools that surface them, and how to act before a problem becomes a crisis.
Analytics8 min
List-Unsubscribe Header: Does It Actually Reduce Spam Rates?
Does the List-Unsubscribe header actually lower spam rates? InboxEagle's study of 19,797 brands reveals a 4.86x extreme spam risk for senders without it.
Klaviyo8 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.
Analytics7 min
The Correlation Between High Sending Frequency & Spam Complaints
Does sending more emails mean more spam complaints? InboxEagle analyzed 31,586 sending programs — the data tells a more nuanced story than you think.
Gmail8 min
Gmail Spam Rate Thresholds: What 0.10% and 0.30% Actually Mean for You
Gmail enforces two spam rate thresholds that most senders misread. Here's exactly what 0.10% and 0.30% mean, how they're measured, and what to do before you breach either one.
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.
E-commerce6 min
What Is a Sending Domain and Why Does It Need Its Own Reputation?
Your sending domain is the identity your email program lives or dies by — and it's separate from your website. Here's what it is, why it needs its own reputation, and what most Klaviyo senders get wrong about it.
E-commerce7 min
Email Domain Reputation: How It's Scored and How to Protect It
Email domain reputation is the primary signal ISPs use to route your campaigns. Here's exactly how it's scored, what damages it fastest, and how to protect it before the next send.
Gmail8 min
Gmail Promotions vs Spam: Where 671K Ecommerce Emails Landed
We measured Gmail placement for 671,329 emails across ~19,400 ecommerce senders in Q1 2026. Brand-level deliverability turns out to be close to binary — and the middle ground barely exists.
Analytics8 min
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.