Email Validator

Validate email address syntax, check MX records, and detect common issues.

What This Validator Checks

RFC 5322 Syntax
The email format conforms to the internet email standard.
Address Length Limits
Local part ≤64 chars, domain ≤255 chars, total ≤254 chars.
TLD Validity
Top-level domain must be alphabetic and at least 2 characters.
No Consecutive Dots
Double dots (..) are invalid in email addresses.
Disposable Domain Detection
Flags addresses from known throwaway email services.
MX Record Lookup
Checks DNS to verify the domain can actually receive email.

Frequently Asked Questions

Does this tool verify that the mailbox actually exists?

No. Confirming mailbox existence requires sending a real email and checking for a bounce. SMTP probing (RCPT TO verification) is blocked by most modern mail servers to prevent email harvesting.

Why might a real email address fail the MX check?

MX lookups can fail due to temporary DNS issues or unusual configurations. Some valid domains use A records instead of MX records. A failed MX check is a warning, not definitive proof the address does not exist.

What is the maximum length of an email address?

RFC 5321 limits the whole address to 254 characters. The local part (before @) is limited to 64 characters. The domain is limited to 255 characters.

Does this tool store the email addresses I enter?

No. Email addresses are used only to perform the validation checks in real time and are not stored, logged, or shared with any third party.

When You Actually Need This

Cleaning up a mailing list before a large campaign is the most common scenario. You have a CSV of 5,000 subscribers and notice a few addresses like [email protected] or test@@example.com. Running suspicious addresses through a validator catches these obvious typos and syntax errors before you send the campaign. This protects your sender reputation — if you send to too many invalid addresses, ESPs like Gmail or Outlook will flag your domain as spam. Checking the MX records also tells you if the domain is even capable of receiving mail, which is a stronger signal than just checking the syntax.

Debugging "why didn't I get the email" support tickets is another frequent use. A user claims they didn't receive their password reset link, but your logs show the email was sent successfully. Looking up their address in an email validator might reveal that their domain's MX records are misconfigured or pointed to an expired service. This allows you to tell the user "your domain isn't set up to receive mail" rather than fruitlessly debugging your own SMTP server. It also helps with data entry — if you're manually adding users to a system and want to ensure the address is at least formatted correctly, a quick validation check prevents "fat-finger" errors from entering your database.