TL;DR
- lemlist alerts at 10% bounces and auto-pauses above 50%, once 100 leads have been contacted.
- lemlist's own advice is stricter: stay under 3%, and pause above 5% to clean the list.
- Don't wait for either. Verify leads before they go in, and aim for under 2%.
How lemlist handles bounces
According to lemlist's help center (checked 2026-10-17):
| Bounce rate | What lemlist does or advises |
|---|---|
| Under 3% | The rate lemlist recommends keeping |
| Above 5% | lemlist advises pausing active campaigns and assessing the damage |
| 10% | Bounce rate alert is triggered |
| Above 50%, after 100 leads contacted | Campaign is paused automatically |
The automatic pause is a last-resort brake. By the time half a campaign has bounced, the sending domain has taken serious damage. The alert at 10% is already double the point where lemlist says you should stop. In practice, the 5% advice is the one to act on, and you have to act on it yourself.
Why a 10% alert is too late
Across the wider market, the numbers are much lower. Smartlead reports a median cold email bounce rate of 1.54% across more than 850 million sends, treats 2-4% as a warning and above 4% as too high, and Instantly pauses campaigns at 5% by default. See our bounce rate benchmarks and how many bounces it takes to burn a domain.
A campaign that reaches lemlist's alert is bouncing at more than six times the median sender's rate.
Where lemlist bounces usually come from
- A stale import. A list pulled months ago, or a lead database export, has decayed since. People change jobs and their old mailbox closes.
- Catch-all leads. lemlist shows these as "Accept All" under Risky. Their servers accept every address and can bounce later. In Hunter's test, they bounced 27% of the time versus 1% for valid addresses.
- Later steps of the sequence. A campaign that was clean on step 1 can bounce more weeks later, as the list ages inside it.
- Too much volume too soon. lemlist suggests 30-40 emails a day per new mailbox, and warming new domains before cold sending.
What to do if your lemlist bounce rate is high
- Pause the campaign if it's above 5%. Don't wait for the 10% alert.
- Export the leads that haven't been contacted yet.
- Verify them in MailExchange. Remove undeliverable and disposable addresses.
- Pull catch-alls into their own campaign, sent slowly from established mailboxes, or drop them if the domain is new.
- Check authentication. lemlist's checklist also covers SPF, DKIM and DMARC, and blocklist checks.
- Re-import and resume at lower daily volume, then watch the next few hundred sends.
Judge the rate over a few hundred sends, not the first dozen. Two bounces on a 20-email day look alarming but tell you little. Twenty bounces on 400 sends is a 5% campaign, and that's when lemlist says to stop. Check the rate per sending mailbox as well, because a healthy campaign average can hide one mailbox that's bouncing far more than the rest.
If the domain is already struggling, follow how to recover a burned domain.
lemlist's built-in verifier vs verifying first
lemlist can verify leads itself. Verification costs 1 credit per lead, and finding plus verifying costs 5, at $0.01 per credit (lemlist credits, checked 2026-10-17). It shows catch-alls as "Accept All" under Risky.
| Option | Cost per verified lead |
|---|---|
| lemlist verification (1 credit) | $0.01 |
| MailExchange 10K ($49) | $0.0049 |
| MailExchange 100K ($299) | $0.0030 |
MailExchange credits never expire, and unknowns and duplicates are refunded. Our results also separate catch-all, role and disposable inside the risky group, so you can decide how to treat each one. Compare at your own volume with the cost calculator, or see pricing.