CATEGORY: Email marketing

Hard Bounces vs soft bounces and what to do with them

Hard Bounces vs soft bounces and what to do with them

We’re going back to basics for this piece to define some terms that are key to understanding deliverability.

What is the difference between a hard and soft bounce?

We like to think about the bounces in terms of time; with a soft bounce likely to be a short term block or short term issue and hard bounces (invalid email addresses and nondeliverables) are permanent issues and should be added to our suppression list.

An email bounce signifies the non- delivery of your message. When this happens the mailer receives an automatic notification of the delivery failure.  Usually the bounce message will help you identify the reason for the delivery failure.

Soft bounce vs hard bounce

A soft bounce is when the bounce is temporary which means that the email address was valid and the email message reached the recipient’s mail server. However, typical reasons for a bounce back include:

  • The mailbox was full (the user is over their quota)

  • The receiving server was temporarily down

  • The message suspected to be SPAM or SPAM related

A hard bounce occurs when the message has been permanently rejected. Typical reasons for this include:

  • The email address is  invalid

  • The email addresses doesn’t exist

  • Mail server doesn't exist

When this happens, we at e-shot™ add the hard bounced addresses to a global suppression list.  What this means is that even if you try to send a message to that contact again we will not try and deliver to that address as we know it is no good – so it is filtered out of your send. Continuing to try to send to a known bad address will harm your reputation with the receiver, so we prevent that.

What is the difference between a soft bounce and a hard bounce? (Plus 3 ways to reduce them)

Reducing your bounces

The best way to reduce the number of bounces is to follow some key email deliverability best practices such as

  • Using an engaged list: Spring clean your list regularly to remove invalid emails and unresponsive contacts. High bounce rates can affect your sender reputation so keeping your list clean will help you in your quest for higher delivery rates.

  • Use double opt-in the belt and braces approach to data collection, it might mean that your list size is smaller, but does guarantee that your contacts will be engaged.

  • Monitor and manage your deliverability with our Forensics tool to review your deliverability. Assess any content and infrastructure issues before you send your mail out into the world.

Achieving high delivery rates can be a challenge but with the help of e-shot™account managers and our forensics tool, powered by send forensics, the first class intelligence could be the difference between a successful campaign and an outstanding campaign

We can also help you clean your lists with our email validation process. Validating an email list is a process to check out whether the list of email addresses is valid and deliverable without actually sending an email, so speak to our Customer Success Team, drop us an email at or call us on +44(0)20 3320 8750 and speak to us about adding Forensics to your email optimisation armoury.

Watch our webinar

There are many technical elements to making sure your email marketing gets delivered, but the most important aspects of good deliverability relate to your data and your content. Learn about the five things you should be doing to keep your emails out of junk in our dedicated webinar.   

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