Email Address Validator - Check Syntax and Domain

What does this tool check?

This tool performs two checks on an email address. First, it validates the syntax against the standard email format rules - checking that the address has a local part, an @ symbol, and a valid domain. Second, it looks up MX records for the domain to confirm it is configured to receive email.

It does not send a test email and does not contact the recipient's mail server (no SMTP probe). This means it cannot detect whether a specific mailbox exists or is full. For most use cases - checking whether an address is likely valid before sending - syntax and MX checks are sufficient.

What makes an email address valid?

Email addresses follow the format local-part@domain with these rules:

• Local part (before @) can include letters, numbers, and . _ + - characters.
• The @ symbol must appear exactly once.
• Domain must have at least one dot and end with a valid TLD (like .com, .org, .io).
• Local part cannot start or end with a dot, and cannot have consecutive dots.
• Total length must be under 254 characters.

Why check MX records?

An email address can have perfect syntax but still be undeliverable if the domain has no MX records. This happens with domains that exist (a website may be live) but are not set up for email. Checking MX records catches problems like:

• Typos in the domain (e.g., gmial.com instead of gmail.com)
• Domains that have expired or had their MX records removed
• Custom domains with a website but no email hosting configured

Limitations of this tool

Even if syntax and MX records pass, an email address may still bounce because:

• The specific mailbox does not exist at the mail server
• The mailbox is full
• The mail server has spam filters or rate limits
• The domain uses a catch-all that silently discards mail

Definitive validation requires attempting delivery, which comes with deliverability risks. This tool gives you a fast, safe check that catches the most common problems without sending anything.

FAQ

Can this tool tell me if a Gmail or Outlook address exists?

No. Gmail, Outlook, and most major providers block SMTP probing (connecting to the server and checking if a mailbox exists without actually sending). This tool confirms that gmail.com or outlook.com is valid and has MX records, but cannot verify a specific inbox.

The MX check passed but my emails still bounce - why?

MX records confirm the domain is set up for email, but the specific mailbox may not exist or may have been deleted. Common reasons for bounces despite a valid domain: the address was mistyped, the recipient left the company and their account was removed, or the mailbox is over quota.

Is the email address I enter stored?

No. This tool processes the address to check syntax and perform a DNS MX lookup. No data is logged or stored.