Bulk email verifier
Upload a spreadsheet of email addresses and get every row back marked valid, risky, invalid or unknown. Your own columns stay intact, so the file drops straight back into your email platform.
How it works
- 1
Upload your CSV
Choose a CSV file. MailSure finds the email column, ignores blank rows and skips duplicates for free.
- 2
Watch it run
The list is checked in the background with live progress. You can leave the page and come back; large lists keep running.
- 3
Download what you need
Download everything, or only valid, valid plus risky, or invalid. Status, score, reason and flags are added to the right of your original columns.
Why use MailSure for this
You pay for answers, not guesses
Unknown results (addresses a server would not confirm either way), duplicates and malformed rows are never billed, and a cancelled list is refunded for the rows not yet checked.
Credits never expire
Buy a pack once and use it whenever. There is no monthly commitment, and a renewing free allowance covers small jobs.
Reasons, not just a colour
Each row says why it failed: no mail server, disposable domain, shared role address, likely typo, or mailbox not found.
See how the price compares in the pricing comparison, or try the free email checker first.
Frequently asked questions
- How long does bulk email verification take?
- It depends on list size and how quickly the receiving servers answer. Small lists finish in minutes; very large lists take longer, and you can close the page while they run.
- What file formats can I upload?
- CSV files. Export from Excel or Google Sheets as CSV first. Any number of other columns can come along.
- How much does it cost to verify a list?
- 100 verifications a month are free. Beyond that, packs start at $4 for 1,000, with 10,000 for $20 and 100,000 for $100. Unknown results are not billed.
- Is my list kept?
- Lists and their results are deleted automatically after a retention period, and you can delete one yourself at any time from its page.