Free Email Validator Online — Check Deliverability & Domain Health

How to use

Single address

1. Open the Single tab (shown by default).
2. Type or paste one email address into the input field and click Validate.
3. The result panel shows a status badge (Valid, Invalid, Warning, or Role-Based) and a breakdown of each check.

Bulk validation

1. Click the Bulk tab.
2. Paste a list of email addresses — one per line — into the text area.
3. Click Validate All. The tool processes each address and produces a results table.
4. Use the filter buttons to view All / Valid / Invalid / Role-Based results.
5. Click Copy Valid to copy only the clean addresses.

Saved Lists

The Saved Lists tab stores validation sessions for the current browser session. Switch between past validation runs to compare results.

How it works

Each email address is validated in four stages:

1. Syntax — checks the address against RFC 5321/5322 format rules: local part characters, single @, valid domain format, label lengths, and overall length limits.

2. DNS/MX lookup — calls the server's DNS resolver to check whether the address's domain has at least one valid MX record. A domain with no MX records cannot receive email.

3. Disposable detection — checks the domain against a regularly maintained blocklist of known disposable and temporary email services.

4. Role-based detection — checks the local part (the part before @) against a list of common role-based prefixes: info, admin, support, sales, contact, noreply, help, billing, webmaster, postmaster, and others.

Worked example

Common validation statuses explained

Tips for list hygiene

• Validate before every send — list quality degrades over time as subscribers change jobs and domains expire. Re-validate lists older than 6 months.
• Remove role-based addresses from marketing sends. They frequently trigger spam complaints or go unread. Keep them only for transactional email where the recipient is specifically that team.
• Do not rely on MX check alone for cold outreach. A valid MX record means the domain can receive mail — it does not mean the specific address has ever been used.
• Use the bulk validator before importing into your CRM. Importing invalid addresses raises your bounce rate, which damages your sender reputation with ESPs like Mailchimp, Klaviyo, and Brevo.

What a passing validation does not guarantee

A result of "Valid" means the address is well-formed, the domain has mail servers, it is not a known disposable domain, and it is not role-based. It does not mean:

• The mailbox exists. Many domains accept mail at any address and silently discard unknown ones. This is called a catch-all configuration. An MX check will pass; the email will never be read.
• The mailbox is active. A former employee's address on a company domain may have valid MX records long after the account was deleted.
• The message will not be filtered. SPF, DKIM, and DMARC alignment issues — which are sending-infrastructure problems, not address problems — determine whether the message lands in the inbox or spam folder.

The only way to confirm inbox-level deliverability is to send a message and observe the bounce response.

Corporate and enterprise domain behaviour

Large organisations using Microsoft 365 or Google Workspace often configure mail acceptance policies that differ from standard MX behaviour. Common patterns:

• Microsoft 365 domains typically return a 550 error for non-existent users only after the message is accepted — making SMTP-level verification unreliable. An MX check will pass for any address at a Microsoft 365 domain.
• Google Workspace domains behave similarly but sometimes expose unknown-user responses at the SMTP RCPT TO stage with recipient verification enabled.
• Vanity domains on shared hosting (e.g., [email protected] pointing to cPanel mail) can have MX records but misconfigured mail servers that reject all incoming mail silently.

For cold outreach to corporate addresses, treat a "Valid" result as a green light for sending — but track hard bounces after the first send and remove any addresses that bounce 5xx immediately.

Internationalised email addresses

RFC 6531 (Email Address Internationalization) allows non-ASCII characters in both the local part and the domain. Examples: उपयोगकर्ता@उदाहरण.भारत, 用户@例子.广告. These addresses require UTF-8 support across the entire mail path (sending server, receiving server, and MTA relay chain). The validator checks for RFC 5321/5322 ASCII syntax; internationalised addresses outside the ASCII range will show an invalid-syntax result unless your sending infrastructure explicitly supports EAI.

Sources

• RFC 5321 — Simple Mail Transfer Protocol
• RFC 5322 — Internet Message Format
• IETF — Email Address Internationalization (EAI), RFC 6531

Last updated: October 2026