The Prime Verifier Blog
Practical guides on email deliverability, list hygiene, and sending best practices, so you get the most from every campaign.
How to Write Subject Lines That Avoid Spam Filters
Some perfectly innocent subject lines still trigger spam filters because of specific word and formatting patterns. Here is exactly what to avoid and why.
Read articleHow to Improve Email Open Rates
Open rate improvement is not just about writing better subject lines. Here are the specific, measurable levers that actually move this metric, in order of impact.
How to Reduce Your Email Spam Score
A high spam score is never caused by one single factor. Here is a breakdown of the specific signals that drive it up and the concrete steps to bring it down.
How to Check if Your Domain Is Blacklisted
If your deliverability has suddenly dropped, checking blacklist status is the fastest way to confirm whether that is the cause. Here is exactly how to do it.
Envelope From vs Friendly From: What Is the Difference?
Every email carries two different sender addresses at once, one for routing and one for display. Understanding the difference clarifies how authentication actually works.
What Is a Return Path Email Address?
The address that receives your bounce notifications is often not the same one your recipients see. Here is what a return path is and why the distinction matters.
What Is TLS Encryption in Email?
TLS is the encryption layer protecting most email in transit today, though it works differently than most people assume. Here is exactly what it does and does not protect.
What Is an Email Header and What Does It Actually Show?
Every email carries hidden technical data explaining exactly how it traveled and whether it passed authentication. Here is what an email header actually shows and how to read it.
What Is a Mail Server and How Does It Work?
A mail server is the piece of infrastructure that makes email delivery possible at all. Here is what it actually does and how it connects to deliverability.
What Is BIMI and How Does It Work?
BIMI puts your logo directly in the inbox next to your emails, but only if your authentication is already strong. Here is exactly what it requires and how it works.