I or L Checker
Runs in your browserTell l, I, 1, O and 0 apart — and catch invisible or fake Unicode characters.
Colour-coded
l
Lowercase letter L
I
Uppercase letter I
1
Number one
O
Uppercase letter O
0
Number zero
·
Invisible character
а
Unicode lookalike
Nothing is sent anywhere — this runs entirely in your browser. An invisible character is a non-breaking space or zero-width character picked up when copying from Word or a web page; it silently breaks keys and API tokens. A Unicode lookalike is a Cyrillic or Greek character that renders identically to a Latin letter — the classic trick for faking domains and hiding code.