See how much of your list would bounce
Drop a CSV of up to 5,000 rows and see in seconds how much of it would bounce. Every row is checked for bad syntax, duplicates, typo, disposable and dead domains, and 25 addresses get a live mailbox check with their mail server. Free, with no signup.
Drop your CSV here, or
No signup. The file stays in your browser.
Or paste addresses
Syntax, duplicate and typo checks run in your browser. Only domain names are sent for the MX and disposable lookups. Up to 25 addresses spread across your file are sent to our verification server for a live mailbox check; like any check, those results may be cached for 14 days. The file itself is never uploaded.
What the free check tells you
- Problems on every row. Bad syntax, duplicates (including Gmail dot and +tag copies), misspelled domains, disposable providers, role addresses such as postmaster@, and domains that cannot receive mail. These are counted exactly.
- A live spot check. 25 addresses from across the file are checked with their mail server, and the result is used to estimate your bounce rate.
- Risky addresses. If a mail server will not confirm a mailbox, usually because it accepts every address (a catch-all), we report it as risky rather than guess that it is valid.
The full verification checks every address the same way and gives you separate valid, risky and invalid files to download. See pricing.
Common questions
- How does the free check work?
- Every row in your file is checked for bad syntax, duplicates, typo domains, disposable providers and domains that cannot receive mail. Then 25 addresses from across the list get a live mailbox check with their mail server, which shows how many real mailboxes are missing. Together they tell you how healthy the list is before you send anything.
- Why are only some addresses checked live for free?
- A live mailbox check is the expensive part of verification, so the free check runs it on a spot sample to show you whether the list is in good shape. The paid plan runs it on every address and gives you a clean file to send to.
- Is my file uploaded?
- No. The file is read in your browser. Domain names are sent for the MX and disposable lookups, and only the sampled addresses are sent to our verification server. As with any check, a sampled address's result may be cached for 14 days so it is not checked twice.
- What do I get if I pay?
- Unlimited verification for $29.99 a month: upload the same file, every row gets the SMTP check with catch-all detection, and you download valid, risky and invalid as separate CSVs with your original columns. Files can be up to 100,000 rows. Cancel anytime.
- How many times can I use the free check?
- As often as you like. The live spot check runs once an hour, on 25 addresses at a time.