How to Verify an Email Address

Email verification confirms whether an email address is real, active, and able to receive messages. Running verification before you send protects your sender reputation and keeps bounce rates low.

Steps to Verify an Email Address

1. Check the email syntax

Confirm the address follows the standard format: local-part@domain.tld. Watch for missing @, extra spaces, or illegal characters. This catches typos instantly — no network request needed.

2. Validate the domain

Look up the MX (Mail Exchange) DNS record for the domain. If no MX record exists, the domain cannot receive email and the address is undeliverable.

3. Perform an SMTP check

Connect to the mail server via SMTP and ask whether the mailbox exists — without sending a real message. A 250 OK response means the mailbox is live; a 550 means it does not exist.

4. Flag catch-all and role addresses

Some domains accept all email regardless of the mailbox (catch-all). Others belong to roles like info@ or support@, which have low engagement. Mark these separately so you can decide how to treat them.

5. Use a bulk verification tool for lists

For large lists, upload a CSV to BillionVerify. It runs all checks in parallel and returns a cleaned list with a status for every address — valid, invalid, catch-all, or disposable.

Tips

• Verify addresses at the point of collection — before they enter your list.
• Re-verify old lists every 6–12 months; mailboxes go stale.
• Never send to addresses that return a hard bounce a second time.
• Keep your bounce rate below 2% to protect deliverability.

Recommended Tools

• BillionVerify Email Checker — Verify a single address instantly — no sign-up required.
• BillionVerify Bulk Email Verification — Upload a CSV and verify thousands of addresses at once.
• BillionVerify Email Validation API — Real-time verification via REST API for any stack.