Definition: In email marketing, a soft bounce is an email which is temporarily undeliverable, usually because of some problem on the recipient's side. Soft bounces are measured in ecommerce email marketing campaigns, indicating addresses which are still usable but currently unavailable.
A high bounce rate indicates that a mailing list may be old, inaccurate or filled with fake addresses. Any bounce rate over 8 percent is in danger of not only wasting resources, but running afoul of whichever email service you utilise.
While soft bounces indicate a temporary problem, hard bounces are emails that will never be deliverable, usually because the address doesn't exist. Soft bounces indicate that the address exists and is correct, but couldn't be delivered. Some reasons soft bounces occur are:
Some emails that are returned as undeliverable may not tell you why they couldn't be delivered, but others will provide a code which indicates the bounce type. Knowing and interpreting bounce codes is the first step to distinguishing between these two types of failed emails.
A soft bounce means that you can try to send the message again in hopes that the problem will be fixed. Some email marketing services will resend soft bounces automatically, but after a set number of tries, will give up and label the address as a hard bounce.
Keep in mind that soft bounces do not result from blacklists or spam filters. If your marketing email gets shunted into an email provider or individual user's spam folder, you may never know. It's important that you utilise strategies that minimize both bounces and spam labeling:
Email marketing is still a very successful strategy for driving website traffic. Soft bounces and bounce rates in general are a good metric for knowing if your mailing lists are as good as they could be.