TL;DR
- One balance for every client. Buy credits once and use them on any client's list. They never expire.
- Catch-alls split out from deliverable leads, so you decide per client how much risk to take.
- From $0.0017 per email at 1M, unknowns and duplicates refunded, and an API (early access) for your pipelines.
Why agencies need to verify every list
An agency's problem is scale. You're importing lists from clients, Apollo, Clay and data vendors into dozens of campaigns across many sending domains. Each platform has its own bounce brake: Instantly pauses above 5% after 200 sends, Smartlead's protection is off unless you turn it on, and lemlist doesn't pause until 50%. A client's "clean" CRM export or a stale vendor list can burn the domains and mailboxes you've spent weeks warming.
Verifying before import is the cheapest protection you can buy, and it's easy to standardise: every list, from every source, goes through the same check before it touches a sending tool.
How agencies use MailExchange
- Upload each client's list as CSV or TXT, or paste it. Their columns are kept, so the file goes straight back into the sequencer.
- Read the results: deliverable, risky (catch-all, role or disposable, each labelled), undeliverable or unknown.
- Apply your client's risk rules. Send deliverable. Put catch-alls in a separate, slower campaign, or skip them on new domains.
- Import the clean file into Instantly, Smartlead or whichever tool that client uses.
The full process, with links for each platform, is in how to verify emails before cold outreach.
Credits shared across clients, and they never expire
Client work is lumpy. One client launches 80,000 leads this month, another pauses for a quarter. With MailExchange, credits sit in one balance and work on any list. They never expire, so you can buy a bigger pack at a lower rate without worrying about losing what you don't use this month.
| Pack | Price | Per email |
|---|---|---|
| 50,000 | $179 | $0.0036 |
| 100,000 | $299 | $0.0030 |
| 250,000 | $599 | $0.0024 |
| 500,000 | $999 | $0.0020 |
| 1,000,000 | $1,699 | $0.0017 |
Pay as you go. Monthly plans are 15% off. Unknowns and duplicates are refunded. Full price list on pricing, and a side-by-side with the big names in verification pricing compared.
That's also cheaper than paying for verification inside each client's sequencer. Instantly's verifier costs about $0.0078 per lead on Growth, and Smartlead's starts at about $0.0053. Run your numbers in the cost calculator.
Catch-alls are a per-client decision
B2B lists are full of catch-all domains, which accept every address so no verifier can confirm the person exists. In Hunter's test (checked 2026-10-17), they bounced 27% of the time versus 1% for valid addresses. Some clients can afford that risk on a separate campaign, and some can't. We label catch-alls separately so you can choose for each client. More in should you send to catch-all emails?
Automate it with the API
If your leads flow through Clay, n8n, Make or your own scripts, call the MailExchange API before leads are pushed into a client's campaign. Verify one address in real time, or submit up to 100,000 addresses in one call and get a callback when it's done. The API is in early access. Ask for a key.