How to reduce your email bounce rate

Hard bounces and soft bounces

• A hard bounce is permanent: the address does not exist, or the domain does not accept mail. Never try that address again.
• A soft bounce is temporary: a full mailbox, a server that is down, a message that is too large. It is fine to retry for a while, and then give up.

What is a good bounce rate?

Aim for under 2% of messages bouncing. Many senders see well under 1%. Above that, mailbox providers start to see you as someone who sends to addresses they did not collect carefully.

Email services set their own limits, because one customer’s bounces affect everyone sending through the same infrastructure. SendSend, for example, warns you at 2% hard bounces and pauses sending at 4%, so a mistake in a list cannot cost you your reputation overnight.

Why addresses bounce

• Typos at signup. gmial.com, hotmial.com, a missing letter. The most common cause by far.
• Fake or throwaway addresses entered to get past a form.
• Old lists. People change jobs and abandon mailboxes. A list that was good two years ago is not good now.
• Bought or scraped lists. Full of dead addresses and spam traps. Do not use them.

The fixes that work

1. Check addresses as they are typed. A good check catches bad syntax, domains that do not exist, throwaway providers, and likely typos, and can say “Did you mean gmail.com?”. How to do it at signup. You can try it free with the email checker.
2. Confirm new subscribers. A confirmation email (double opt-in) proves the address is real and the owner wants your mail, before it joins your list.
3. Suppress hard bounces immediately. The first hard bounce should stop all future sends to that address. SendSend does this automatically.
4. Retire people who never engage. If someone has not opened or clicked anything in six to twelve months, stop emailing them, or ask whether they still want your mail.
5. Watch the numbers weekly. A spike after an import or a campaign points straight at the cause.

Bounces versus complaints

They are different problems. A bounce means the address was bad. A complaint means a real person pressed “this is spam”. Complaints are weighted much more heavily, and providers expect them to stay far below 0.3%. Make your unsubscribe link easy to find: a person who cannot leave will report you instead.