What is an Email Validator?
An email can be well-formed and still undeliverable: the domain decides. Real validation checks both: the format, and whether MX records exist to receive mail.
The syntax check runs locally; the MX check queries live DNS. What no tool can promise is whether the specific mailbox exists, only the receiving server knows that at delivery time, and we say so instead of pretending.
Frequently asked questions
Can any tool verify a mailbox exists?
Not reliably: servers deliberately don’t reveal it (to block address harvesting). Services claiming 100% mailbox verification are overselling.
What are MX records?
DNS entries naming the servers that accept mail for a domain. No MX (and no fallback A) means mail cannot be delivered.
Why validate before sending?
Bounces hurt your sender reputation: enough of them and real recipients stop getting your mail.
Is the address I type stored?
No, only the domain part is looked up in DNS; nothing is retained.