Email Address Checker

About this tool. When an email does not arrive you are left guessing between two very different problems: the address is wrong, or the address is fine and something is stopping your mail. This checks everything that can be established without sending anything: whether the address is formed correctly, whether the domain exists, whether it is set up to receive email at all, whether it is a throwaway provider, and whether it looks like a near-miss of a common one. What it deliberately does NOT do is open a connection to somebody else's mail server to ask whether the mailbox exists. That technique is unreliable (large providers answer identically for real and fake addresses), rude, and gets the prober blocklisted, which would be an odd thing for a service that tells you whether you are on blocklists.