Your email marketing campaign looks flawless and is rich with the details of your product. It shows your customers precisely how they can get one for themselves and the savings and benefits they stand to gain from their purchase.

However, if that email doesn’t reach their inbox, and fails at the first step, your sales funnel rendered useless, and your ROI is zero.

So, what prevents emails from reaching their intended destination? And once you’ve figured out where the problem is, how do you go about putting it straight?

It all boils down to email deliverability. We’re going to explain what that is and what impacts its efficiency, so you can create the best possible chances of getting your sales funnel into peak working order, and your ROI exactly where it should be.

What is the sender reputation, and how does it affect deliverability?

Sender reputation is a measure of how trustworthy the email address is. It’s used by ESPs to decide which messages are considered genuine and allowed access to their servers, and which aren’t.

This screening process filters out vast quantities of emails, and in a recent survey by Return Path, sender reputation was said to account for over three-quarters of delivery problems.

What earns an email address a poor sender reputation?

Bounce rates, complaint rates, and spam trap hits.

If you want a healthy sender reputation, these are the main culprits you need to avoid:

  1. Your bounce rate is the number of undeliverable emails as a percentage of the total amount of emails sent.
  2. The complaint rate is the number of emails marked as spam as a percentage of the total amount of emails sent.
  3. Spam trap hits are the percentage of the emails in your database created explicitly to trace spam senders.


The higher your bounce rate, complaint rate, and spam trap hits become, the worse your sender reputation.

The worse your sender reputation becomes, the less likely your messages are to arrive at their destination, or worse still, be blocked completely.

There aren’t hard and fast numbers for sender reputation cut-off points, as each ESP works within their own systems and regulations. That’s one reason why we need to strive for the healthiest lists possible, at all times.

Even with only a slightly poor reputation score, some providers will send your messages into junk and spam folders. Over time, those results will drag your reputation lower still, leading to partially or fully blocked addresses.

Improving sender reputation with email validation service

Email validation is one of the best ways to create a healthy database of active addresses, filtering out those doing the damage to your sender reputation. There are strategies you can carry out manually, or you can automate the entire process.

The benefits of using an automated service are many, and every email marketer should be taking full advantage of the tools on offer.

Reduced bounce rates

Email validation will protect your database from the addition of invalid addresses, or remove them during a scan. The more invalid addresses you remove, the higher the percentage of emails are delivered.

Fewer spam complaints

Monitoring how recipients treat your campaigns provides opportunities to reduce the number of messages marked as spam. This lowers the complaint rate and improves your reputation.

Increased delivery rates and improved metrics

As your reputation increases, more messages will reach the intended inboxes. And, with more opportunities for open and click rates, you will score higher conversion rates through additional sales.

Filtering out fraudulent addresses

Validation services detect those addresses that aren’t associated with a genuine user account. Addresses containing anything other than a name before the @ symbol will be scrutinized. Any bot or spammer-generated addresses waste your resources and damage your deliverability.

Lowering costs

If you use a dedicated email service that charges per unit, removing all of the useless addresses will save you money. A smaller, more effective, filtered, and cheaper to deliver database will not only achieve better results, but it will also increase your ROI.

The crucial elements of any email address validation service

Validating email addresses can be as simple or as complicated as you’re prepared to make it. The deeper you clean, however, the more beneficial it is to your campaign results, so be thorough, and reap as much reward as you can.

Stripping out syntax errors

A sophisticated validation service is programmed to recognize a huge amount of human and bot-based issues. However, there are so many different email address formats to consider.

It’s difficult for programmers to create algorithms capable of spotting all the various anomalies.

With formatting rules changing from provider to provider, some software scripts will reject acceptable, valid addresses, destroying valuable leads as they do. The free services won’t run as sophisticated checks as their paid-for competitors, meaning their level of cleanliness will be lower, resulting in poorer deliverability.

Where that margin means the difference between landing in a lead’s spam folder or inbox, it’s time to consider if that’s the best option for you.
Human error plays a huge part in syntax issues. Typos are commonplace on web-forms, with Gmail being labelled Gmial, or a suffix missing a letter or a dot.

Not being able to read a healthy lead’s handwriting on a customer comment form, or the addition of tags when copy and pasting from another program—they all lead to errors and invalid entries.
Checking for typical errors and putting them straight helps to make the most from healthy leads instead of deleting them and losing valuable opportunities.

Confirmation of an email domain

Users buy domains and create addresses for all kinds of reasons, yet many of these will never have a mailbox set up to accept communication. Validating domains have been shown to find up to 3 times more invalid entries than through syntax errors.

Some validators carry out checks in real-time, which can sometimes return less accurate results. The Internet isn’t a perfect system, with network outages, service updates, and downtimes, each of which can mean an unfortunately timed check will dictate a healthy address as unknown

Validation of domains is far more accurate when carried out through continual monitoring, over several days as opposed to seconds or minutes. With this deeper-dive option, only when a domain continues to fail through regular checks is it finally classed as invalid.

Mailbox validation

Mailboxes are created and deleted at a high rate, with users swapping out email addresses for all sorts of reasons. Changing jobs, switching services, business rebrands, and more—all add up to the number of mailboxes that were active only a few months ago, yet have been replaced by a new option.

It’s one of the biggest hitters during validation. The technique used to check a mailbox’s validity is known as pinging. When your software pings a mailbox, it checks its availability by pretending to send an email, without actually sending a message.

This way, you’re address is protected from bounces, yet retrieving all the information you need.

Recognizing problem addresses

There are many types of email addresses to be avoided if you’re going to keep a clean and healthy recipient list. Some of the following industry terms explain which they are and the damage they can do.

Complainers are the people who regularly report commercial email marketing campaigns as spam. Screamers are those who will go a step further to complain about any unwanted email. Neither of these will help your campaign data, so monitor for them and strip them out wherever you can.

Fake addresses are often used to access the data a user is trying to protect. Spammers use bots to compromise web forms and then spam anyone they can access through them. The addresses they use often end up in polluted lists.

Role-based accounts can also cause issues for marketers. Although they are genuine addresses with active mailboxes, they are almost always monitored by a team of people.

Designed for a particular task, these accounts are rarely suitable for marketing. Sending to these accounts regularly results in being moved into a spam folder by one or more of the recipients.

When to utilize email validation?

There are 3 main points where email validation is a must.

1. At the point of entry
Validating addresses as they’re harnessed means that any new entries uphold the list, keeping it clean and healthy.

2. Before send out
A database that hasn’t been used for some time will have produced several out-dated and expired addresses. To protect your sender reputation and deliverability, this is the time to validate your list; removing any addresses that will exceed the limits and thresholds set by ESPs.

3. For continued email hygiene
Once you’ve got a clean and healthy list, you should implement a schedule to keep it that way. Regular validation will keep your data clean and always campaign ready.

Choosing a reliable email validation service

We believe Bouncer is one of the best email validation services on the market.

Our simple tool will help keep your data clean, your bounce rate low, and your ROI exactly where you need it to be. If you’d rather hear it from our existing users, why not read our email validation service reviews available on G2 and Capterra?

If you’d like to hear more, give us a call. Our team of experts is always ready and waiting to answer your questions.