A hard bounce occurs when an email can’t reach the recipient due to permanent delivery issues, such as invalid, closed, or non-existing emails. Unlike a soft bounce, which is usually a temporary failure – for example, if the inbox is full or the server is down – a hard bounce occurs when the email can’t be delivered under any circumstances.
Email deliverability depends on proper email list cleaning by the companies periodically, which is done through verification facilities to strike out invalid or cold addresses to avoid spam or blacklisting.
How does hard bounces affect companies
- 15-20% of all business emails bounce, with hard bounces accounting for almost 8%.
- Email lists decay at 22.5% annually, meaning almost a quarter of your contacts become invalid yearly.
- Anything over a 5% bounce rate can cause email providers to classify senders as spammers, reducing their placement in the inbox (similar to email blacklisting).
- Companies that clean their email lists every six months see a 35% increase in email deliverability and a 20% increase in engagement rates.
- In 2025, AI-driven email verification tools are expected to cut hard bounces by 50%, leading to better ROI on email and lead conversion rates.
Here’s what the experts have to say
If your emails are not reaching inboxes, your campaigns are worthless.
Experts also emphasize that regular list management, strategies for double opt-in, and real-time email verification tools are all about sustaining high deliverability rates. Companies that disregard bounce rates risk losing contact with their audience and gradually degrading their email marketing returns.
Real case studies
Amazon sends millions of transactional emails daily, including order confirmations and shipping updates. To reduce hard bounces, it developed an AI-powered email validation solution that pre-checks the addresses before an email is triggered in real-time.
This proactive strategy reduced hard bounce rates by 40%, ensuring better inbox placement and higher customer engagement. In addition, Amazon flags outdated or inactive addresses to avoid affecting the sender’s reputation.
On the other hand, Netflix relies heavily on email notifications to send account updates, new show recommendations, and reminders. However, outdated emails resulted in high bounce rates, which affected user engagement. In that respect, Netflix implemented progressive email verification, identifying and removing the accounts of those no longer active before sending emails.
The good news? Netflix reduced bounces by 30% and improved opens by 25%, along with click-throughs.
Netflix doesn’t mess around with their email game – when they send those perfectly timed suggestions straight to your inbox, it’s because they’ve done their homework. Every single “Check this out!” note comes from really knowing who’s watching what. The way they drop those show recommendations feels natural because they’ve studied what makes us click play at 2 AM. They’re pretty good at figuring out what’ll keep us glued to our screens next. You know that feeling when your best bud suggests exactly what you need to watch? That’s what they’re going for, and they nail it most of the time.
The problem with a hard bounce
The most frequent problem that hard bounces present to businesses involves list decay: email addresses become invalid due to changes in employment, shutdowns, or inactive accounts. Because 22.5% of all email addresses become obsolete each year, neglecting to manage this decay leads to high bounce rates, reduced engagement, and poor sender reputation.
A solution falling into routine in this direction involves preliminary address validation, a process of double opting-in, and verification powered through AI.
Your checklist to avoid a hard bounce
- Use AI-powered services that detect invalid emails before sending them.
- Ensure users confirm their email addresses to reduce mistakes.
- Regularly purge addresses that show no engagement over 6-12 months.
- Look for patterns and adjust email acquisition strategies.
- Authenticating your emails using SPF, DKIM, and DMARC will help improve deliverability.
- Pre-send test emails using appropriate tools, which can detect probable spam triggers.
- Create a list of new contacts and one for those who are inactive to avoid sending possibly outdated emails.
