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MailCull

MailCull blog: field notes on email deliverability and list quality

2026 9 of 32

Why Are My Emails Bouncing? A Diagnostic Walkthrough

The bounce report has the answer. You just need to read the codes.

September 3, 20267 minbounce-rate

What Is a Spam Trap? Types, Risk, and How to Stay Off Blacklists

Pristine, recycled, typo: three types of spam trap, three different signals about your list hygiene.

August 31, 20268 mindeliverability

What Is a Disposable Email Address? (And Why They Distort Your List)

A disposable address isn't a fake address. It's a real one nobody's ever going to read.

August 28, 20266 mindisposable-email

What Actually Happens When You Send to an Invalid Email Address

One bad address doesn't just bounce. It nudges every subsequent send a little closer to the spam folder.

August 25, 20267 mindeliverability

SPF, DKIM, and DMARC Setup: A Practical Guide With Real DNS Records

The three records, real examples, and the safe rollout sequence.

August 22, 20267 mindeliverability

Role-Based Email Addresses: What They Are and When to Mail Them

A role-based address isn't automatically bad. It just behaves differently than a personal one, and the right call depends on what you're sending.

August 19, 20266 mindeliverability

MX Record Validation: What It Actually Tells You About an Email Address

If the domain has no MX, no mail lands. But a healthy MX record proves less than people think. Here is where the signal stops being decisive.

August 16, 20267 minemail-validation

How to Reduce Your Email Bounce Rate: The Complete 2026 Guide

Bounce rate is a single number with five different causes underneath. Here's how to find yours and fix the right one.

August 13, 20268 minbounce-rate

How to Clean an Email List: The Complete Practical Guide

Eight steps. One sitting. The list you start with isn't the list you should send to.

August 10, 202610 minlist-cleaning
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