I was astounded by how many terms I needed to learn when I first tried my hand at email marketing. For the first few months of learning about email marketing, I was at a loss as to what terms meant.

What were the most complex terms for me? Hard and Soft Bounces

Sure, I was aware that these were email delivery terms. One was always bad, while the other was not. And I always got them mixed up (even today, I have to triple-check to make sure I’m on the right track).

Simply put, when you send an email, it is directed to a specific recipient. An email server is in charge of receiving emails. If this server is unable to deliver the email to that particular person, it returns the email with an error message. As a result, the email bounces.

The reason for the email’s failure to deliver is what distinguishes a hard bounce from a soft bounce. And because these two types of bounces are among the most important email marketing metrics to track, let’s look more closely at these email marketing terms and their distinctions.

What is a Hard bounce?

A hard bounce is a permanent bounce email, which means that an email sent to that address will not be received. It could be due to an unknown user error, which occurs when an email address:

  • Is invalid because it does not exist or contains a typo (for example, @gmial.com rather than @gmail.com).
  • Has been deactivated, such as when a person leaves a company or discontinues use of a free email account
  • Your emails have been blocked from being delivered.

Effectively managing hard bounces is a critical step in cleaning up your email list. While most email service providers (ESPs) handle this for you, it’s worth investigating your specific ESP’s policies to ensure this process is in place. Do they correct common email address typos automatically? After all, those hard bounces, will your email service provider mark an email address as undeliverable? And for what types of hard bounces?

If you handle bounces individually, you could delete the email addresses, but as part of your list hygiene practices, I suggest deactivating them or attaching them to a suppression list. This eliminates the possibility of sending to email addresses that you know will hard bounce.

What is a Soft bounce?

A soft bounce is a temporary bounce, which means that while the delivery of your current message failed, you may be able to deliver another email to that address at a later time. It may be bouncing because of:

  • Far too many people have marked your emails as spam.
  • You’ve been added to a blocklist.
  • The recipient’s inbox is overflowing.
  • The email account is currently suspended.
  • Unanticipated mistakes or outages at the receiving mail server.

Temporary bounces do not usually require immediate attention because they resolve on their own, but they should be monitored closely. BriteVerify Founding Partner Matt McFee suggests treating soft bounces the same as hard bounces. After three bounces, you should remove the email from your list. It’s also critical to understand the period during which those bounces occurred: Was it over a single day or a week?

Enquire your ESP about what they do about soft bounces as well. Do they try to resend your message automatically? When and also, how many times are they going to give up? When does a soft bounce become an undeliverable email address on your suppression list?

Hard Bounce vs. Soft Bounce email: What’s the Difference? 

When an email bounces, it means it was unable to be delivered to an inbox. The terms “hard” and “soft” refer to two types of failures: one that is more permanent and one that is less permanent.

A hard bounce is an email that was unable to be delivered for unclear reasons. Perhaps the email contains a forged address, the email domain is not a legitimate domain, or the email recipient’s server refuses to accept emails. There are multiple reasons why an email may be a hard bounce, but the main one is that it is a permanent failure. Delete all of these addresses from your list.

A soft bounce is an email that was unable to be delivered due to unforeseen circumstances. For example, an inbox may be full, or the email file may be too large. When an email service receives a soft bounce, it will keep attempting to deliver the email for several days. Keep an eye on these addresses; if you notice that the same ones appear over and over, it’s best to remove them.

Try to keep your total bounce rate under 2%; anything higher than that will result in deliverability issues.

That’s all there is. Hard bounces are long-term delivery failures. Soft bounces are temporary failures to deliver. It’s not as complicated as it appears, but it’s just as important.

Final Words

When either a hard or soft bounce occurs, it’s time to roll up your sleeves and get to work on your lists. Sending emails to hard-bounced addresses repeatedly can indicate to internet service providers (ISPs) that you have poor list hygiene practices.

I recommend reviewing your bounce statistics at least once a week. You may want to check more frequently, or more frequently during peak seasons, based on the scale and scope of your email marketing program.

Data quality is an essential metric for ISPs when determining whether or not your emails are spam, and it can affect your sender’s reputation.

Active list management improves not only deliverability but also engagement. (This, in turn, enhances deliverability.) When you send to a cleaner list, you increase your chances of reaching people who want to receive and interact with your email. That’s a win-win situation.