OpenSheetFree tool · no sign-up · 1,000 contacts a month
Free bulk email and phone verifier
Paste a list of business contacts and check every email address and phone number in one go. Free for up to 1,000 contacts a month, with no account. Nobody on your list is emailed or called.
Need to find new business leads?
Discover business contacts with OpenSheet, then verify your data in one workflow.
What the verifier checks
Email addresses
- The address is written correctly, and common typos like gmial.com are spotted
- It isn't a throwaway inbox from a temporary email service
- Big providers like Gmail allow a username like it
- The domain exists and has working mail servers (MX records)
- The domain isn't parked or expired, and isn't a catch-all mail host
- The domain's website is online, and its SPF and DMARC mail setup
- Shared inboxes (info@, sales@) and low-trust domain endings are flagged
Phone numbers
- The number is a real, correctly formed number for its country
- US and Canadian area codes are assigned; 555 and filler numbers are caught
- The line type: mobile, landline, internet (VoIP), toll-free or premium rate
- With a website: whether the business's own site lists the same number
- With an address or country: whether the number is from the same country
These are the same checks OpenSheet's paid verifier runs on its customers' lead lists. What they can't do: confirm a specific inbox exists (no email is sent and no mail server is asked about the inbox) or tell whether a phone line is connected right now (no number is called).
What the results mean
Emails
- Deliverable
- The domain exists, its mail servers accept email and nothing about the address looks wrong. Safe to send to.
- Risky
- It may work, but something is off: a likely typo, a little-used mail setup, a shared inbox or a domain whose website is down. Check it before you send.
- Catch-All
- The mail server accepts every address at the domain, so this exact inbox can't be confirmed without emailing it.
- Undeliverable
- It can't receive email: a broken format, a domain that doesn't exist or has no mail server, a throwaway inbox, or a parked or abandoned domain.
- Unknown
- We couldn't finish the check (usually a mail server that didn't answer in time). Try it again later.
Phone numbers
- Valid
- A correctly formed, assigned number for its country and a normal line type. When you include the website, it's also compared with the numbers on it.
- Risky
- The number exists but may not reach the business: an internet (VoIP), toll-free or premium line, a website that shows a different number, or a website that's offline.
- Invalid
- It can't be a working number: the wrong length, an area code that isn't assigned, or a placeholder like 555 numbers.
- Unknown
- A local number with no country to read it by. Add the country code (like +44) or choose the country for local numbers.
How the free checks work
- 1,000 contacts a month, free. Counted per internet connection, so there's nothing to sign up for. They come back on the 1st of each month.
- One line is one contact. A line with an email and a phone number uses one check, and both are checked.
- Repeats don't count. Lines with the same email and phone are checked once. Results you already have in this tab aren't checked again, and the exact same list run again within 24 hours isn't counted twice.
- Over the limit? The first contacts that fit are checked and the rest are marked Not checked, ready to download and verify in an OpenSheet account.
Checking one address instead?
The free email checker checks a single email address and shows each step: format, throwaway inbox, domain, mail servers, provider, website and anti-spoofing setup. Use this bulk verifier for lists, and phone numbers too.
Questions & answers
Is the bulk verifier really free?
Yes. Every internet connection gets 1,000 free contact checks each month, with no account and no card. A contact is one line of your list, and its email and phone are both checked. The free checks come back on the 1st of each month.
Do you email or call the contacts on my list?
No. Nothing is sent to anyone and no number is called. Emails are checked through the domain's public mail records (DNS) and its website; phone numbers through numbering data and, when you include it, the business's website.
Can it tell if a specific inbox exists?
Not for certain. That would mean connecting to the mail server and asking about the inbox, which many servers refuse or answer falsely, and which this tool doesn't do. It tells you whether the address can receive email at all and flags the signs of a bad one. Catch-All means the server accepts every address, so the inbox can't be confirmed.
Can it tell if a phone line is connected?
No. It checks the number is real and correctly formed for its country, what kind of line it is (mobile, landline, VoIP, toll-free) and, with a website, whether the business lists the same number. It doesn't place a call.
Do you store my list?
No. Your contacts are checked and sent back to your browser, and they're never saved on our servers or used for anything else. The results stay in this browser tab until you clear them or close it. We keep only counts: how many checks your connection used this month, and each domain's public mail setup so repeat checks are faster.
What happens when I reach the free limit?
The rest of your list is marked Not checked and you can download it. A free OpenSheet account verifies another 1,000 leads a month: upload the file there. Pro verifies up to 25,000 leads a month.
How should I format my list?
One contact per line, with the email, phone and website separated by commas, tabs or semicolons. Copying rows straight from Excel or Google Sheets works. A header row (Email, Phone, Website, Country) is optional; without one, each value is recognised by what it looks like.
Verifying bigger lists every month?
OpenSheet Pro verifies up to 25,000 leads a month ($49/month), removes the bad ones from your sheet and finds new leads with verified emails.