Invisible character

Six characters that render as nothing or as blank space, with a note on each about whether platforms accept it. The Hangul filler and the blank Braille cell are the two that usually survive.

These are not spaces in the sense a keyboard produces, and that is the point — a platform that rejects an empty name will often accept a Hangul filler, because as far as its validation is concerned there is a character there. The zero-width ones are different: they have no width at all and are frequently stripped on save, so they work for hiding a marker inside text rather than for making a blank name. Two warnings worth taking seriously. Zero-width characters have been used to fingerprint documents and messages, so text you received containing them may carry an identifier. And they break string comparison invisibly, which is the reason text cleaners exist.