In practice, “email validator,” “email checker,” and “email verifier” are used almost interchangeably.
When people do draw a line, it usually looks like this:
- Validation checks whether an address could be real. It looks at syntax (an @ sign, no illegal characters), confirms the domain exists, and checks that the domain has MX records set up to receive mail. It catches typos and junk, but typically misses addresses that look fine but still won’t work: non-existent or full mailboxes, disabled accounts and disposable addresses.
- Verification goes further and checks whether the mailbox actually exists and accepts mail. It talks to the receiving mail server (an SMTP connection, without sending a message). This is what catches addresses at real companies where the person has left.
In short, validation asks “is this a properly formed address that looks deliverable?” and verification asks “will a message to this address actually land?” No Más Rebotes does both and also flags disposable addresses, catch-all domains and role-based addresses.