Bounce Rate: Hard Bounce vs Soft Bounce

For a long time, when an email was bouncing, I thought: this email does not exist. Of course, I was wrong. Emails can bounce for many reasons.

When an email bounces, it just means that the recipient's server did not accept it. This server usually replies with an email including details about the specific problem (we call this a non-delivery report or NDR).

We can divide the type of bounces into two categories: the hard bounces and the soft bounces. A hard bounce is generally permanent meaning that even if you send the same email again, the recipient's server will continue to reject it. On the other hand, soft bounces are temporary. There is a chance the email may be delivered later.

A hard bounce happens because the recipient's email address does not exist, the person left the company, or someone simply made a typo while typing it. Whatever the reason, you should permanently remove them from your lists.

Soft bounce, on the other hand, indicates that an email address is valid but that your message could not be delivered. This situation can result from different factors: the recipient's server has a technical issue (crash, maintenance, not configured correctly), the mailbox is full and cannot receive any more emails, your message is too large, etc.

Your marketing software will try sending again in the coming hours/days. It will designate a soft bounce as a hard bounce between three and five failed attempts. For full mailboxes, I remove them from my lists as I consider these users inactive. Also, when a server repeatedly bounces on different emails, it probably means that it probably means that it is definitely out of service.

People move from one company to another, get fired, or pursue new challenges more frequently than you think. This tricky situation increases the number of hard bounces you get. At ProspectWith, we have worked hard to ensure every prospect we provide is still working inside the company. This feature is one of our main advantages and the result of many algorithms.

When I read pending bounce, I read soft bounce while keeping in mind that the server will attempt to deliver the email for a while. I like to keep things simple, and the difference is just too subtle to create a third category for me.

You should not. Even if some people consider it a soft bounce. Here is why: your email was successfully delivered to the inbox.

When you try to contact big corporations, government institutions, schools… their servers are usually more strict and can block your emails if they detect something wrong. Each IT department has its own rules, so it can be challenging to investigate. The IPs of your marketing software could be in a blocklist because of a low reputation, and your message may include forbidden content. You may also do not have the right to message this person. Once again, I permanently delete these addresses from my list, and I try to contact the recipients on another channel like LinkedIn, Twitter, or phone.

Of course, almost all marketing software will notify you about hard bounces and will prevent you from emailing these contacts again by cleaning your lists for you. It makes sense if you think about it, as a high bounce rate can lead to a lousy email sender reputation and decrease deliverability.

You can get the bounce rate with the following formula (you do not have to calculate it every time you send an email as your marketing software will give it to you).

Email bounce rate = (number of emails bounced / number of emails delivered) x 100

Of course, you will never get to a 0% bounce rate, so don't be disappointed. You are nothing to worry about if you are below 5% overall bounce rate (soft and hard). Above 10%, start to inspect the quality of your leads because it could harm your email deliverability, and you could get restrictions from your marketing software.

I tend to ignore them. First of all, the authors usually aggregate internal data made to attract new customers. Results change over time, and if the analysis is older than three years, it is probably better to ignore it. I prefer to follow one simple rule: stay under 5%.

Let's start with the most simple one: don't buy email lists when you are unsure if the email addresses are verified. Or, if you do, make sure to use a service to validate your emails and clean the list from spam traps, invalid emails, and domains that do not exist anymore. This is also a good practice if you have an inactive email list. I consider a list to have gone stale when it is dormant for over six months.

If I may, we have designed ProspectWith to provide you with all the decision-makers that match your ideal customer in less than three clicks. To ensure every professional email exists, we are using multiple email verifiers. We know a lot on this subject, so feel free to ask me in the chatbox if you want to save time and get the best solutions available in the market (the ones that do not cheat).

Now you understand why double opt-in is essential. If they must confirm their email, you will exclude all the fake emails. The only downside is that you will lose many people who are valid emails but did not click on the link to verify it (around 20%). Despite this, I generally prefer to get rid of it to avoid being trapped by invalid emails or spam traps.

It is best to use a reputable provider to send your emails. I would avoid using a free service like Gmail or Yahoo. Your bounce rate will not be the same, especially if you are looking to contact large companies or government institutions. Your emails will fail a DMARC check. Your IP will probably have a low reputation, and many other factors will get your emails rejected.

Apart from that, inserting a link to unsubscribe is critical. It is a legal requirement in many countries (even for prospecting emails if you do not offer a straightforward way to exit the sequence). It will also avoid being marked as spam which will increase the reputation of your sender's IP address.