Free email checker

What do valid, risky and invalid mean?

Valid means the mail server confirmed the mailbox, invalid means mail to it will bounce, and risky means the mailbox could not be confirmed either way.

Valid

The mail server confirmed this specific mailbox exists. Safe to send.

Risky

The domain is fine but the mailbox is unconfirmed — most often a catch-all domain that accepts every address, or a server that greylisted the probe. Deliverable more often than not, but send these in a separate batch.

Invalid

This will hard bounce. The mailbox does not exist, the domain has no mail server, the syntax is broken, or it is one of 9,913 known disposable domains.

How do I verify an email address without sending an email?

Ask the recipient’s mail server instead of the mailbox. An SMTP check connects to the server named in the domain’s MX record, says who the mail is for with RCPT TO, reads the reply and hangs up before the message stage, so there is nothing to deliver. A 250 reply means the server accepts mail for that mailbox; a 550 5.1.1 means it does not exist.

The tool above runs that conversation for you, after checking the syntax and the domain. Doing it by hand with telnet works too, but many home and cloud networks block outbound port 25, which is why a hosted checker is easier. The longer explanation is in how to check if an email is valid without sending.

How can I tell if an email checker really checks the mailbox?

Give it an address you know is fake and see whether it says invalid. Invent one at a real domain, something like [email protected], and check it here. It should come back invalid, because the mailbox genuinely does not exist and Gmail says so.

Run the same address through any other tool. If it returns valid, that tool checked the syntax and the domain and stopped there; it never asked about the mailbox. That is the difference between a verifier and a formatter, and it is the reason lists that verify clean still bounce.

How do I check if an email address is valid?

1. 1Type or paste one address into the box, for example [email protected]. You can run five checks a minute, no account needed.
2. 2Press Check. The tool checks the syntax, looks up the domain's MX records, then asks the mail server about the mailbox with RCPT TO and disconnects before any message is sent.
3. 3Read the verdict: valid, risky or invalid, with the mail server's reason underneath.
4. 4If the result is risky, test the domain with the catch-all checker. For more than a handful of addresses, run the file through the email list health check first.

Example

You enter

One address: [email protected].

You get

Valid, with the reason "Mailbox exists": the mail server accepted the mailbox at RCPT TO and the tool disconnected before any message was sent. A mailbox the server won't confirm comes back risky, never valid.

Limits

Five checks a minute per IP address, one address at a time, no account needed.

Is an SMTP check better than a syntax check?

A syntax check reads the address. An SMTP check asks the server that would receive the mail. They catch different problems:

A regex such as ^[^@\s]+@[^@\s]+\.[^@\s]+$ accepts any invented address at a real domain. Only the receiving server knows whether the mailbox exists, as described in RFC 5321.

Who uses this tool, and for what?

Cold emailers

Check the one address you found for a key prospect before it goes into a sequence, so a typo or a departed employee does not count against your bounce rate.

Recruiters

Confirm a candidate's address from a CV or a referral before sending an offer or an interview invite that has to arrive.

SaaS teams

When a user says they never got the confirmation email, check the address they signed up with. An invalid result means the typo is theirs, not a delivery problem on your side.

Sales ops

Spot-check a few rows of a vendor's lead file before buying or importing the rest. If invented-looking addresses come back valid elsewhere and invalid here, the vendor never checked the mailboxes.

What can’t this tool tell you?

• On a catch-all domain the server accepts every address, so the mailbox cannot be confirmed and the result is risky. No verifier can do better without sending.
• Some servers accept every recipient during the SMTP conversation and only bounce the message later. A valid result from those servers can still bounce.
• Greylisting, timeouts and servers that block verification connections also produce risky, because no clear answer came back.
• It is limited to five checks a minute, and mailbox checking has a daily capacity. When that runs out, the result is based on DNS only and says so.
• A valid result is true at the moment of the check. It does not tell you who reads the mailbox, whether they want your email, or whether it is a spam trap.

Sources

• RFC 5321: Simple Mail Transfer Protocol
• RFC 3463: Enhanced Mail System Status Codes

Common questions

How can I check if an email address is real?

Connect to the domain's mail server and ask whether the mailbox exists, without sending a message. That is what this tool does: it checks the syntax, looks up the domain's MX records, then opens an SMTP conversation and issues RCPT TO for the address. A 250 response means accepted, a 550 means the mailbox does not exist. Nothing is delivered and the recipient never sees anything.

Will the person receive an email when I check their address?

No. The check ends before any message is transmitted — the connection is opened, the address is named, the response is read, and the connection closes. No subject, no body, nothing arrives in their inbox.

Why does it say risky instead of valid?

Because the mailbox could not be confirmed. The usual reason is a catch-all domain, which accepts mail for every address whether it exists or not, so no verifier can tell a real mailbox from an invented one there. Greylisting and servers that refuse to answer also produce risky. We report that honestly rather than guessing valid.

Is this email checker free?

Yes, five checks a minute with no account. Sign in with Google and you also get 100 free email checks for a list, no card. Paid plans are for bulk work: Starter $9 a month for 2,500 emails a month, or Pro at $39 a month for verification that is never cut off (the first 100,000 a month at full speed), CSV uploads up to 100,000 rows and the email finder.

What does verify email address mean?

It means confirming an address can receive mail: the syntax is correct, the domain has a mail server, and that server says the mailbox exists. Apps also use the phrase for the confirmation link they send you, which proves you own the address rather than that it works.

How do I check if a Gmail address is real?

Enter it above. Gmail's servers answer the mailbox question like any other, so an invented Gmail address comes back invalid and a real one comes back valid. Dots in the part before the @ do not matter to Gmail, so [email protected] and [email protected] are the same mailbox.

Can I verify email addresses in bulk for free?

Up to 100 addresses, yes. Sign in with Google, paste the addresses or drop a CSV, and each one gets the same mailbox check as this tool, with results to download. No card. The free email list health check also cleans a CSV of up to 5,000 rows in your browser (duplicates, bad syntax, typo and dead domains) without asking mail servers. Past 100, plans start at $9 a month for 2,500 emails a month.

How accurate is email verification?

For addresses at ordinary domains it is definitive — the mail server itself tells you whether the mailbox exists. It cannot be definitive on catch-all domains, which is why an honest tool has a risky category. Any verifier claiming near-perfect accuracy with no risky bucket is hiding its uncertainty inside its valid results, which is where unexpected bounces come from.

Have a whole list?

Upload a CSV of up to 100,000 rows and get valid, risky and invalid back as separate files. Pro is $39 a month, no credits, never cut off: the first 100,000 a month run at full speed. See pricing or try the other free tools.