Homograph & Confusable Character Checker

In short Cyrillic а, Greek ο and fullwidth Ａ are different characters that render as ordinary Latin letters, and that is the whole basis of lookalike domain and username attacks. A domain registered with a Cyrillic а in the middle is a completely different domain from the one it imitates, and to the eye there is no difference at all. This flags mixed scripts and names the specific confusable characters it finds. Two things worth understanding about the result. Mixed scripts are not automatically an attack — a name written in two languages, a citation, or a mathematical symbol in prose are all legitimate reasons for a string to span scripts, and the tool reports rather than accuses. And a clean result is not a guarantee of safety, because an attacker can stay within one script: rn looks like m, l looks like I in many fonts, and 0 looks like O, none of which involve a second alphabet at all. Browsers defend against this by showing the Punycode form of a mixed-script domain, but the protection has gaps and does not extend to usernames, package names or file names, which is where this check earns its place.