Your designers and copywriters have created an awesome email. You’ve spent time building a targeted list and sent them a couple e-blasts. The issue?

Chances are there might be email bounces and some are delivered to promotions or spam. If an email landed in a spam folder, then did it ever existed? Well, it’s a slim chance that readers would fish out this email and read it. But don’t worry, we will walk you through everything you should know about email deliverability.

What is email deliverability

Email deliverability is the ability the of sending IP delivers emails to subscribers’ inboxes. For instance, a delivery rate is 90% means 90% of the emails have reached your subscribers. This is how some marketers will gauge the likelihood of email campaigns reaching the subscribers’ inboxes based on factors like ISPs, throttling, bounces, spam issues, and bulk sending.

Factors that lower deliverability include emails without custom authentication, using single opt-in, sending from a free domain email address, using email subject lines in a high pressure sales pitch, making it difficult to unsubscribe, using URL shorteners, and sending emails with too many images or links.

How sender reputation affects deliverability

Sender reputation is the reputation of your email gateway, an IP that sends email for your email client. So how does sender reputation work? What exactly are the factors that increase or decrease your sender reputation?

Email deliverability is driven by sender reputation. Here are ways you can improve your sender reputation.

i. Be Consistent in your sending volume

ii. Validate the receiving emails before sending to lower bounce rates

iii. Send emails to opt-ins only 

iv. No spam traps

v.  No blacklists

Let’s find out.. what you can do in practice.

1. Be consistent with your volume

Try to evenly distribute your email campaigns

A consistent volume of email campaigns, without major drops or spikes, plays a significant role in sender reputation.

For example, if you send out an email to your list twice a week, switching to three times a week, will cause ripples.

There will be times when you will want to send out more emails than normal. For example over the busy Christmas period. But aim for a regular, consistent schedule where possible.

Your list will soon get to know your schedule, which will help to increase open rates and click-throughs.

2. Maintain list hygiene

Clean your lists.

At Ideaggio, we use ZeroBounce, NeverBounce, Debounce, and MyEmailVerifier to validate emails.

Some other alternatives include Data Validation, Email List Verify, and Clearout.


Bounces are emails that fail to reach the subscriber. They are a waste of resource. There are two types of bounces, soft & hard.

Soft Bounce

A soft bounce occurs when you send to an inbox that is full or a recipient replies with an “auto-reply” or “out-of-office” message.

Hard Bounce

A hard bounce occurs when your message was sent to an inbox that doesn’t exist. Maybe there is someone who used a fake email to sign up to your list or have changed the email provider. Either way, you don’t want these emails to be ended up in your email list.

Spam complaints (kills your list)

This is something you should watch out! Spam complaints takes a toll on your sender reputation. When subscribers hit the “mark as spam” button, mailbox providers like Gmail, or ESPs like SendGrid receive a notification.

The bad news?

Even senders with just a handful of complaints are blocked by mailbox providers. Some or more restrictive than the others – with a threshold of up to 2% spam complaints. For this reason, bought list is not recommended as it could skyrocket your spam complaints.

Ways to maintain good sender reputation

Stay away from spam traps

Yes.. it’s best to have no fictitious emails in your list. Basically spam traps are emails coming from web scrapers. They are fake emails intended to catch unscrupulous marketers. Any legitimate business should avoid using spammers to harvest emails. After all, sending even a small amount of emails to those email addresses automatically marks the sender as a spammer. Clearly this is unnatural, and it’s not a way to grow your contacts.

How not to get yourself blacklisted

Blacklists are a list of sender domains (ie:, IP addresses, and servers that have been caught sending email spam. Sending emails from a blacklisted IP and domain will land your emails in junk folder or worst yet, it ended up nowhere.

So what gets you blacklisted?

Well, maybe you have a domain that was previously used by a spammer. You might have been in a foul play sending bulk emails with your domain name. Whatever it is, there’s still a good chance to get out of the blacklist (if you’ve been there for once). Repeat offenders will have a slimmer chance getting off the blacklist.

MxToolBox is a tool that monitors black lists. You can use mxtoolbox to check if your server or domain has been blacklisted.

Test example

Here’s an example of a blacklisted domain.

Sender Domain Reputation