TL;DR
- Smartlead's verifier is an add-on (from $32 per 6,000) that runs only at CSV import.
- It sends to catch-all leads by default, and catch-alls are where hidden bounces come from.
- Smartlead's bounce auto-pause is off unless you turn it on.
- MailExchange labels catch-alls separately, verifies any list at any time, and refunds unknowns. Credits never expire.
The catch-all problem in Smartlead
Smartlead's help center says it "will send emails only to valid and catch all leads." A catch-all domain accepts every address at the SMTP stage, real or not, and the bounces arrive later. If your list came from Apollo or another B2B database, a large share can be catch-all. Sending to all of them on a new domain is how bounce rates creep past 2%.
MailExchange marks those leads risky: catch-all, separate from role inboxes and disposable addresses. You choose whether they go in, and into which campaign.
How to verify leads for Smartlead
- Export your leads as a CSV (or export a live campaign's leads from Smartlead).
- Verify the CSV in MailExchange. Duplicates are free and unknowns are refunded.
- Split the file: deliverable leads go to your main campaign. Catch-alls go to a separate, slower campaign on your most established inboxes, or get dropped.
- Import into Smartlead and turn on High Bounce Rate Auto Protection for the campaign.
Turn on bounce protection, and know how it counts
Smartlead's auto-protection is opt-in, and its bounce rate divides bounces by total leads in the campaign, not emails sent. Early in a large campaign the rate looks much lower than the real bounce rate on what's been sent. Set a conservative threshold. How Smartlead's bounce protection works.
Cost
| Option | Price | Per email | When it can verify | Catch-alls |
|---|---|---|---|---|
| Smartlead verification add-on | $32 / 6,000 | about $0.0053 | At CSV import only | Sent to by default |
| MailExchange | $29 / 5,000, $49 / 10,000 | $0.0058 → $0.0049 | Any list, any time | Labelled. You decide |
Smartlead pricing from smartlead.ai/pricing, checked 2026-10-17. At 100K emails MailExchange is $0.0030 each.
Automate it
Verify with the MailExchange API, then add only the leads you want with Smartlead's
POST /campaigns/{id}/leads (up to 400 per call). Ask us about early access to a direct connector.