How email verification works: syntax, MX, and SMTP explained (opens in new tab)

"Email verification" sounds like one thing, but it's really a stack of checks of increasing depth and cost. Knowing what each layer actually proves helps you pick the right level instead of overpaying for verification you don't need. Layer 1: syntax The cheapest check: does the string look like a valid email address? A pragmatic regex catches obvious garbage (asdf, a@@b, trailing spaces). It's instant and free, but weak on its own: nobody@asdf.asdf passes syntax and can't receive a single mes...