Zero-Width Space — U+200B

What U+200B is for

Long strings — URLs, file paths, German compound nouns — give layout engines a problem: where may the line break? The Zero-Width Space is the standard's answer. Inserted between characters, it whispers «you may wrap here» without displaying anything. Browsers honor it, which is why it appears inside long links on well-typeset pages.

The character that breaks copy-paste

That same invisibility makes U+200B the classic cause of mystery bugs. Copy a password, a coupon code or a snippet of code from a web page, and a stray zero-width space can ride along. The field then holds something that looks identical to the correct value and is not equal to it — logins fail, searches find nothing, compilers complain about a character they will not show you. When «identical» strings refuse to match, paste them into the test area below: every hidden codepoint shows up as a tag.

Using it deliberately

Deliberate uses are quieter but real: allowing a clean wrap in a long username or hashtag, separating letters so a word escapes naive text matching, or marking text invisibly — several watermarking schemes encode data as patterns of zero-width characters. Note what the table says: White_Space is No despite the name, but Default ignorable is Yes, and many form validators strip default-ignorable characters anyway. For blank names, the Hangul Filler is the safer pick; for hiding inside text, U+200B is the specialist. Its cousins — the Zero-Width Joiner and Non-Joiner — control how neighbouring characters connect, a different job.

Typing and escaping it

In code it is "\u200B" (JavaScript, Python, Java alike); in HTML, ​. On a phone or in a form, the copy button at the top is the practical route — and the generator produces it in bulk when one is not enough.