Free tool
An email list cleaner that uploads nothing.
Paste your addresses or open a CSV file. See which are invalid, duplicated, mistyped, disposable or shared role addresses, then copy or download the clean list. It checks format and patterns, not whether a mailbox exists.
It runs in your browser. Nothing you paste or open is sent or stored.
What the check found
Checked 12 addresses, 2 invalid, 1 duplicate, 3 likely typos, 1 disposable. 8 addresses are in the clean list.
- Checked
- 12
- Invalid
- 2
- Duplicates
- 1
- Possibly the same person
- 1
- Likely typos
- 3
- Disposable
- 1
- Role addresses
- 1
- In the clean list
- 8
Invalid addresses (2)
- Line 9: finn@outlook (no dot in the domain, such as .com). Did you mean finn@outlook.com?
- Line 13: not an address (no @).
Duplicates (1)
- Ben.Okafor@example.com, 2 times. The first is kept.
Possibly the same person (1)
- dev.lark@gmail.com, devlark+waitlist@gmail.com. All are kept.
Likely typos (3)
- Line 4: chloe@gmial.com → chloe@gmail.com
- Line 9: finn@outlook → finn@outlook.com
- Line 10: grace@hotmail.con → grace@hotmail.com
Disposable addresses (1)
- eve@mailinator.com. Left out.
Role addresses (1)
- info@example.org. Kept.
The CSV has one column, email. With a CSV of your own, it keeps your other columns.
In Waitlark
Waitlark checks addresses as people sign up. Disposable domains are blocked or flagged, your choice, and double opt-in is on by default: only people who confirm from their own inbox join the list.
Disposable domains: the open list from the disposable-email-domains project, 9,963 domains, copied on 28 October 2026. Its licence is CC0, which puts it in the public domain.
How the cleaner works
It reads your list line by line, or the email column of a CSV, and puts every address through the same checks. It never contacts a mail server. It looks only at the address and at known patterns, so it can tell you an address is badly formed or on a throwaway domain. Whether the mailbox exists, it can’t tell.
What it checks
- Format
- One @, something before it, a domain with a dot and an ending of letters, no spaces, and only characters email tools accept.
- Duplicates
- The same address more than once, with capitals ignored. The first one stays.
- Possibly the same person
- Gmail addresses that differ only in dots, and name+tag@ next to name@ at the same domain. They’re listed and kept, unless you choose one per inbox.
- Likely typos
- A short list of slips in the biggest mail domains, such as gmial.com and outlok.com, and endings that don’t exist, such as .con. Each gets a suggested fix, and you decide whether to use it.
- Disposable domains
- Throwaway email services, from the open disposable-email-domains list: 9,963 domains, copied on 28 October 2026, licence CC0.
- Role addresses
- info@, support@, sales@ and other shared inboxes. They’re fine on a business list, though a whole team often reads them.
Opening a CSV
- Save the list as CSV, with commas, semicolons or tabs between the fields, and the column names in the first row.
- The tool picks the column with “email” in its name, or the one with the most @ signs. You can pick another.
- A field in quotes stays one field, with commas or line breaks inside it. Two quotes in a row are one quote.
- The download keeps every column of the rows that stay, with the cleaned address in the email column.
What it can’t tell you
- Whether the mailbox exists or is full. Only sending can tell you that.
- Whether the person agreed to hear from you. Cleaning a list doesn’t add consent that was never given.
- Whether a typo fix reaches the right person. chloe@gmail.com may belong to someone other than the Chloe who typed gmial.com, so ask the fixed address to confirm before you send anything else.
Common questions
- Does it check whether an address really exists?
- No. It checks the format and known patterns: the shape of the address, duplicates, common typos, disposable domains and role addresses. It doesn’t contact any mail server and sends nothing, so an address that passes can still bounce. Double opt-in is the check that works: only people who click the link in their own inbox join the list.
- Why are some Gmail addresses marked as possibly the same person?
- Gmail ignores dots before the @, so dev.lark@gmail.com and devlark@gmail.com reach the same inbox. Gmail and many other providers also deliver name+anything@ to name@. The tool lists these groups and keeps every address unless you tick “Keep one address per inbox”: a +tag can be how someone sorts their mail, and on a referral list it can be someone signing up twice.
- Where does the list of disposable domains come from?
- From the open list of the disposable-email-domains project on GitHub: 9,963 domains, copied on 28 October 2026. Its licence is CC0, so anyone may use it. New throwaway services start all the time, so any list misses some.
- Can I open an export from my email tool or a spreadsheet?
- Yes, as a CSV file. The tool finds the email column by its name or by the @ signs in it, and you can pick another. Fields in quotes, with commas or line breaks inside, stay one field, and the download keeps your other columns.
- Is my list uploaded anywhere?
- No. The list is read and checked in your browser. Nothing you paste or open is sent to us or anyone else. The only file the page loads for the check is the list of disposable domains, from this site.
Another question? Chat with us.
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Early access
Early birds get in first.
Join the waitlist for Waitlark. We invite people in small groups, and waitlist members get the early-bird price.
One email to confirm, one when your invite is ready. Unsubscribe in one click. What we store.