Source quality is not delivery proof
A list can look complete and still contain old work addresses, guessed mailboxes, disposable accounts and domains that accept every address. The first campaign is the wrong place to learn which rows were real.
MailValid checks each contact before you send. You get a clear result for valid, invalid, catch-all, disposable and role-based addresses, so your team can decide what enters a campaign.
How to clean a contact list
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1
Upload the CSV. Select the email column; no code or special file layout is required.
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2
Review the result groups. Remove invalid and disposable contacts, and separate catch-all or unknown results.
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3
Download the clean file. Import only the segments that match your sending policy.
Use the right rule for each result
Valid contacts can enter your normal campaign.
Invalid contacts should be removed before the first send.
Disposable addresses should be excluded from sales and marketing lists.
Catch-all or unknown results should be placed in a separate, lower-volume segment.
Role-based addresses need a team policy because intent differs from a named contact.
Where teams use lead verification
Purchased lists before any address reaches a sequencer or email platform.
Scraped contacts after collection and before enrichment is treated as complete.
Agency client lists so one client's poor data does not damage a shared sending setup.
Partner and event lists where age, consent and source quality can vary by row.
Can I verify a purchased or scraped list?
Yes. Upload the file as CSV and review each result before you send. Verification does not replace your duty to confirm that the outreach itself is lawful.
Do I need an API key?
No. CSV cleaning works in the web app. Automated workflows can use the REST API or MCP server.
What should I do with catch-all contacts?
Keep them out of your main segment. Test them in smaller batches and watch delivery results.
Are duplicate contacts charged twice?
Duplicates in the same bulk job are detected so the list does not consume two credits for the same address.
Can an agency verify several client lists?
Yes. Credits are tied to the account, do not expire, and can be used across client files.
Check your next lead list — start with 100 free credits, no card required.