Email Validator

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Understand Email Validator

Checks one address or a whole pasted list for valid syntax, flags likely domain typos, and marks known disposable providers.

How it works

Validation is three separate checks. First the address is tested against a pragmatic RFC 5322 pattern: a local part that may contain letters, digits, and the punctuation the standard permits (including `.`, `+`, `_`, and `-`), an `@`, and a domain of one or more labels ending in a two-letter-or-longer top-level domain. Then the local part is checked for the dot rules the standard imposes — it may not start or end with a dot, and may not contain two in a row. Finally the domain is compared against a typo map (gmial.com, gmail.con, hotmial.com) and a list of known disposable providers. Everything runs locally; no address is sent anywhere.

When to use it

  • Cleaning an imported mailing list before uploading it, so obvious typos do not burn your sender reputation
  • Adding a client-side check to a signup form and wanting to see what a given rule accepts and rejects
  • Checking whether a batch of addresses contains throwaway domains before granting trial access
  • Catching the single transposed character in a support ticket where a customer says they never got the email

Watch out for

  • Valid syntax proves nothing about deliverability. There is no MX lookup and no SMTP handshake here, so a perfectly formed address at a domain with no mail server passes. Only a confirmation email proves a mailbox exists.
  • Dots and plus signs in the local part are legal. `first.last+tag@example.com` is a valid address, and rejecting `+` in a signup form is a bug, not a safety measure — whether a provider treats those as the same mailbox is provider policy, not a rule you can enforce.
  • Some legal addresses are rejected here. Quoted local parts (`"john doe"@example.com`), IP-literal domains (`user@[192.0.2.1]`), single-label domains such as `user@localhost`, and non-ASCII internationalized addresses are all valid in the standard and fail this pattern.
  • The disposable-domain list is fixed and finite. New throwaway domains appear constantly, so an address not flagged here is not proven to be permanent.

Not the right tool for: Verifying that a mailbox actually receives mail. That needs an MX lookup plus an SMTP probe, or a confirmed opt-in email — no amount of regex can establish it.

Frequently Asked Questions

Does validating syntax guarantee the email exists?

No — syntax validation only checks format. To verify deliverability, you need SMTP verification (connecting to the mail server) or sending a confirmation email. This tool checks syntax and flags obvious issues but cannot confirm the mailbox exists.

What common typos are detected?

Gmail.con → .com, yahoo.co → yahoo.com, hotmai.com → hotmail.com, gmial.com → gmail.com, and similar transpositions in common provider domains. The tool also flags missing @ symbols and invalid TLDs.

What is a disposable email domain?

Disposable (temporary) email services like Mailinator, 10-minute mail, and Guerrilla Mail allow anonymous inboxes. The validator flags these using a built-in domain list, letting you decide whether to accept or reject them in your signup flow.

How to Use Email Validator

  1. Paste or type your input in the input area above.
  2. The tool processes your input automatically or click Run.
  3. Copy or download the result using the action buttons.
  4. Use Ctrl+Enter to run quickly from the keyboard.