Note: The following is a guest post by author Krista Barrick, an email verification specialist at a XVerify–one of SendGrid’s solution partners. 

Many marketers don’t know the real risks involved when email bounces. Hard bounces, specifically, cause long-term deliverability problems and even damage your sender reputation.

Before you start to reduce your hard bounces, read on to clarify the differences between hard and soft bounces as well as understand why emails bounce in the first place.

What is a hard email bounce?

Hard bounces result when an email address is permanently non-deliverable. The hard bounce likely occurs because the email address does not exist. When you send to an email account that does not exist you receive a standard “failure to deliver” message. Just like how the mail man or woman cannot deliver your mail if someone did a hit and run to your mailbox.

Hard bounces usually occur because:
• The email address is not a real account
• The email address is fake because it was a typo
• The user once had a real account but closed it
• The user once had a real account but abandoned it
• The employee is no longer with the company

What is a soft bounce?

A soft bounce occurs when a valid email address is unable to receive mail at the moment the sender is trying to send. Note that if you’re using SendGrid’s UI, you will notice that SendGrid reports soft bounces as blocks in the metrics dashboard. Once the issue causing the soft bounce is resolved by the network, the email is usually delivered to the inbox at a delayed result.

Soft bounces can happen if:
• The recipient’s mailbox is full
• The mail server is down

Why do hard bounces damage your inbox delivery?

Each time you get a hard bounce, your reputation score takes a hit. It’s like how your credit score goes down with each credit inquiry. Email sending solutions urge you to have less than a 2% hard bounce rate. Imagine if your hard bounce rate jumps up to 5%, that’s going to have a pretty major impact on your reputation. Your email platform doesn’t want your poor data quality practices damaging their credibility.

Sure, the ESP you are using is not from the Stone Age, and has bounce handling techniques, but what if the unthinkable happens? What if one of your sites gets attacked by a bot? Prevention is always better than cure.

In order to have good inbox delivery, you need to have a good sender score. A sender score is what Internet Service Providers (ISPs) look at to determine if you are good enough to get your message across to their users. Want to find out how to check your reputation? Check out the blog post on 5 ways to check your sending reputation.

Solving Data Quality Problems

Poor data quality and collection methods can result in high levels of hard bounces. Many times, bad email addresses enter your marketing funnel and marketers have no idea until after the hard bounce happens. But, the good news is that there are tools available that can check the accuracy of the email address before the email ID enters your list.

Real-time email verification can be implemented directly with your sign-up form. If a user is on your website, types in their email, and even makes an accidental typo, the verification will alert the user. When a user is aware they made a mistake, they fix it. This way you capture only valid data–the first time.

Validating your data at the point of collection helps you significantly cut down on the number of bogus inbound leads you get and saves you time. As far as older data in your database, it is highly recommended that you clean your entire email database on a quarterly basis. This will help you identify email addresses that were once good, and have now gone bad.


Hard bounce emails are bad for your email performance, and bad for your email sending platform. Keep in mind that hard bounces happen to all marketers, but when your hard bounce rates spike up, you can expect your delivery rates to drop. Following data quality best practices will help you maintain your sender score and improve your reputation.

It is still just Q1 of 2017, so take a moment to clean your entire database if you have not already done so. Remove the garbage emails from your list so that you can see an improvement in your email performance. Place real-time email verification on your landing pages, and have peace of mind that fake accounts are not getting into your funnel.

For more information on how to improve your email delivery rates, check out SendGrid’s 2017 Deliverability Guide.

Krista Barrack
Krista Barrack is an email verification specialist at XVerify. She helps digital marketers improve email campaign success through data verification. Outside of the office, Krista also enjoys traveling, fitness, reading, and listening to podcasts.