Deliverability & Sender Reputation
How to make sure the email you send actually lands in the inbox: the technical and reputational side of sending.
23 guides and growing
Why this matters
Most cold email never fails because of what you wrote. It fails because the receiving server could not trust where it came from. Getting this right is the difference between an email that lands and one that quietly disappears.
What you’ll be able to do
The guides
How to Check Your Email Spam Score Before Sending
A pre-send routine to catch authentication gaps, content triggers, and infrastructure problems before a campaign ever reaches a real inbox.
Complaint Rate and Bounce Rate: The Numbers That Sink Domains
Two metrics decide whether receivers keep trusting you: how often recipients mark you spam, and how often your mail hits dead addresses.
The Complete Guide to Email Deliverability
The pillar guide to email deliverability: reputation, authentication, spam filtering, inbox placement, and list hygiene, with links to every detailed subtopic.
The Complete Guide to Email Authentication
How SPF, DKIM, DMARC, and the newer ARC and BIMI standards prove your mail is really yours, and why cold email fails without them.
Email Blacklists Explained, and How to Get Removed
What DNS blacklists are, how domains and IPs end up on them, how to check, and the steps to get delisted without repeating the cause.
Google and Yahoo Sender Requirements, Explained
Google and Yahoo now enforce authentication, one-click unsubscribe, and a hard spam-complaint ceiling. Here is exactly what each rule asks of you.
Why Did That Email Bounce? Hard vs. Soft Bounces Explained
Not every bounce means the same thing. The difference decides whether you remove a contact or simply wait it out.
How Gmail's Spam Filter Actually Works
Gmail decides placement with authentication rules, AI content analysis, and a hard complaint-rate ceiling. Here is what each layer checks, and how to pass it.
How to Warm Up a Cold Email Domain in 14 Days
A day-by-day warm-up schedule with real volume numbers, what to watch at each step, and the signals that tell you to slow down rather than continue.
Inbox Placement vs. Deliverability: What's the Difference?
Deliverability means your mail was accepted. Inbox placement means it reached the inbox. Confusing the two hides your real cold email problem.
Plain Text vs HTML Email for Cold Outreach
Plain text wins for cold email, but not for the reason usually given. What matters is looking like a person wrote it, and how many links you include.
Before You Hit Send: A Pre-Campaign Deliverability Checklist
A final, practical checklist to run through before launching any cold email campaign.
What Is Sender Reputation, and How Do You Build It?
Sender reputation is the trust score receiving servers assign your domain and IP. Here is what shapes it, and how to build it deliberately.
Spam Trigger Words to Avoid in Cold Email
Modern filters read intent, not a banned-word list, but whole categories of phrasing still skew your score toward spam. Here are the ones to cut.
Verify Your Sending Domain Before Your First Campaign
A step-by-step walkthrough of domain verification in RepMail, the one thing every sending domain needs before you can campaign.
What Are Spam Traps, and How Do You Avoid Them?
Spam traps are addresses that exist only to catch senders with poor list hygiene. Here are the types, how you hit them, and how to keep your list clean.
What Is a Good Spam Score for Cold Email?
Spam scores from SpamAssassin, Microsoft SCL, and provider filters decide placement. Here are the target numbers and what actually moves them.
What Is DKIM, and Why Does It Matter for Cold Email?
DKIM cryptographically signs every message you send so receivers can prove it is really from you and was not altered. Here is how to set it up.
What Is DMARC, and Which Policy Should You Use?
DMARC tells receivers what to do when SPF or DKIM fails, and reports who sends mail in your name. Here is how to roll it out without blocking yourself.
What Is an SPF Record, and How Do You Set It Up?
SPF is a DNS record listing the servers allowed to send as your domain. Here is how it works, how to set it, and the mistakes that break it.
Why Your Emails Land in Promotions Instead of Primary
The Promotions tab is not spam, but it is not the inbox either. Here is what pushes cold email there, and how to write and send for the Primary tab.
New Domain, Poor Delivery? Why You Need to Warm It Up First
A verified domain with no sending history still has to earn trust gradually. Here is a practical ramp schedule.
Why Your Emails Land in Spam, and How to Fix It
SPF, DKIM, and DMARC explained through the problem they actually solve: mail that never reaches the inbox.
How RepMail helps here
The guides teach the craft. These are the parts RepMail handles for you.
Explore RepMail- Guided domain verification with generated DNS records
- Automatic SPF and DKIM record generation
- Bounce and complaint tracking on every campaign