What is bounce rate?
Bounce rate is the percentage of sent emails that could not be delivered. Hard bounces are permanent failures (the address does not exist); soft bounces are temporary (mailbox full, server down, message too large).
Every bounce is an inbox provider noting that you sent mail to an address that couldn't receive it. A few are normal; a lot is a signal that you don't know your list — and inbox providers respond to that signal by trusting you less.
Hard bounces are the dangerous ones. They mean the address simply doesn't exist, which is almost always a list-quality problem rather than a temporary glitch. A high hard-bounce rate is the fastest way to damage sender reputation, because it's the clearest evidence that your data is dirty.
Soft bounces are softer signals: a full mailbox, a server that's briefly down, a message that exceeded a size limit. Most mail systems retry soft bounces automatically, and many resolve on their own. Persistent soft bounces, though, often harden into permanent failures and deserve the same scrutiny.
The fix is upstream. Verifying a list immediately before sending — and removing the invalids — is the most direct way to keep hard bounces low. B2B Database Network verifies at export and refunds the credits for any address that comes back invalid, so the addresses most likely to bounce never enter your send in the first place.
Frequently asked questions
How do I reduce my bounce rate?
Verify the list immediately before sending, remove invalids, send catch-alls in separate tracked batches, and keep your data fresh — re-verify anything older than ~90 days.
What's the difference between a hard and soft bounce?
A hard bounce is permanent — the address doesn't exist. A soft bounce is temporary — a full mailbox or a server that's briefly down. Hard bounces hurt sender reputation most and signal a list-quality problem.