Difference between Hard Bounce and Soft Bounce
Written by
Ninad Pathak
Ninad Pathak

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Difference between Hard Bounce and Soft Bounce

Published : May 21, 2020

In this article, we cover the difference between a hard bounce and soft bounce along with some of the steps to prevent emails from bouncing.

An email bounce is a term used when the email doesn’t reach the recipient’s email address. But why do emails bounce? What is the difference between a hard bounce and soft bounce? And what can you do to prevent emails from bouncing?

Let me address these questions right away in this guide.

Why do Emails Bounce?

Bouncing cat and girl gif
Bouncing ain’t no fun for your emails! – Just like that cat

From the top-level view, there are two types of email bounces:

  • Hard bounce
  • Soft bounce

And these bounce responses can be generated for reasons including the below:

  • Invalid email – Hard bounce
  • Receiver email storage full – Soft bounce
    The email server is offline – Soft bounce
  • The sent email is too large – Soft bounce

When an email doesn’t reach the email address that you specify, the receiving server responds with a bounce response. This bounce response generally has the details about the bounce including why an email bounced, and if it’s temporary or permanent. Now that we’ve already introduced the terms soft and hard bounce, let’s find out the differences between these two types of email bounces.

What’s the Difference Between a Hard bounce and Soft bounce?

Let’s come right to the question and understand what is the difference between a hard bounce and a soft bounce and how to deal with them.

What is a Hard Bounce?

A hard bounce is a permanent bounce. There’s not much you can do to fix a hard bounce from your end since the email that you sent was denied by the receiving server.

When the receiving email server denies the email that you’re sending out to an email address, it is termed as a hard bounce. The server can deny your email if the email address that you’re sending the email to is invalid, doesn’t exist, or is unavailable within their list of registered users.

But how did you end up with an invalid email address on your list? Here are a few possible reasons:

  • The user misspelled their email while registration
  • A user registered with their official email address but they no longer work there
  • The server blocks external emails
  • Invalid email – The email doesn’t exist

What is a Soft Bounce?

A soft bounce is a temporary bounce. This can be due to the server space being full, or the receiving server is temporarily down or a plethora of other reasons.

But all of the situations are temporary and you should be able to send the email again at a later time. When users register with email addresses that are self-hosted or hosted on smaller platforms, there’s a possibility of downtime, incoming email size limitation, or severely limited email storage space.

If any of these conditions are true, the server responds with a soft bounce and your email doesn’t get delivered. But fret not, because these situations are very easy to deal with (and much easier with Pepipost).

How to Tackle Hard Bounce and Soft Bounce?

You got a couple of hard bounces and soft bounces when running your email campaign, what do you do? Let’s talk about how to maintain an exceptionally low bounce rate!

The first thing is to determine the type of bounce and separate the bounced email addresses based on the type.

How to Deal with a Hard Bounce?

Since a hard bounce is a permanent bounce, the list of emails that are under “hard bounce”, should immediately be removed from your recipients’ list. If you continue to send emails to an email address that is invalid, you will hurt your domain and IP reputation in the long run.

How to Deal with a Soft Bounce?

As we already discussed that a soft bounce is a temporary bounce, you can retry sending the emails to the soft bounced email addresses after a few hours or even after a day.

Sending the emails a couple more times to a soft bounced email address won’t hurt you much but maintain caution as having a high percentage of bounced emails is not a good sign.

So if the soft bounce doesn’t resolve in a few days, it’s best to completely avoid sending emails to the list of email addresses for a while.

You don’t need to remove them from your recipients but just suppress them.

Reasons Why Emails Bounce

Now that we’ve covered the difference between a hard bounce and soft bounce, let me share a quick summary of some of the major reasons why emails bounce.

  • Wrong email addresses
    This is one of the major reasons for email bounces since some users who sign up only to gain access to some content can enter emails created by temporary email services (like 10minutemail)
  • Spam Filter
    If your IP has been abused in the past and can no longer bypass spam filters, your emails will bounce right at the spam filter. You can check if emails from your domain are landing in Spam – Email Blacklist Tool
  • Inbox Full
    Another common reason is when the recipient’s inbox is full. This often happens with people on self-hosted or in-premise mailboxes with limited quota
  • Bad Sender Reputation
    This comes down to the IP reputation and domain reputation discussion that we had earlier. Have a look at both the articles if you haven’t already. They sure will help you improve your sending reputation.
  • DNS Verification Records
    This is an easily fixable issue, but still very common because it’s not something that will stop you from sending emails. If the receiving server doesn’t check for these records, your emails will reach the inbox. But if they do check (which is the majority of the mailboxes), then your emails will either bounce or land in spam.

This was the summary of one of our recent articles on the top 5 reasons why emails bounce. Do have a read through if you’d like to reduce your email bounce rates!


I hope you now have a perfect idea of what the difference between a hard bounce and soft bounce is and how you can deal with email bounces. If you’ve been experiencing a lot of email bounces lately, it’s a perfect time for you to consider switching to another ESP.

We have a guide that talks about how to choose the best email service provider and if you’re still confused, we’re always available to answer all your queries (look, Pepi is waving at you at the bottom right!). We have maintained a >95% email deliverability rate and continue to allocate a lot of company resources to find ways to improve email delivery and inboxing.

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Written By: Ninad Pathak