ZeroWidthSpace

Zero Width Space (ZWSP) refers to the Unicode character U+200B, known as the zero width space. It is an invisible formatting character that has a width of zero and is categorized as a formatting character (Cf) in Unicode. Because it does not render as a visible glyph, ZWSP can be inserted into text without altering its visible appearance.

In practice, ZWSP is used to indicate boundaries or potential line break opportunities without adding visible spacing. Rendering engines may permit a line break at the ZWSP position according to the Unicode line breaking rules, while preserving the adjacent characters as if no space had been inserted. The character itself does not create a visible space, nor does it join characters; it simply marks a potential breakpoint in the text.

Common applications include text processing and typographic control, where a boundary marker is needed without changing the visual layout. ZWSP can also play a role in systems that require token separation or in languages and scripts where a visible separator would be undesirable. It is distinct from other zero-width characters used for shaping or joining text, such as the Zero Width Non-Joiner (U+200C) and the Zero Width Joiner (U+200D).

Zero width characters, including ZWSP, can be exploited for steganography, encoding data invisibly within ordinary text. For this reason, some software and filters may strip or normalize zero-width characters, which can affect their use in message formatting or data embedding.