Why invisible characters appear
Unicode includes controls that do not display like ordinary letters. They may be inserted by word processors, websites, document converters, multilingual layout systems, copy-and-paste operations, or automated tools. Some are legitimate; others create unexpected search, parsing, layout, or comparison problems.
Supported character groups
Zero-width characters
UnmarkAI checks common zero-width spaces and joiners, the word joiner, and the byte-order mark within pasted text.
Direction controls
Bidirectional controls help render right-to-left and left-to-right languages. Removing a legitimate control can change display order, so multilingual text must be reviewed.
Soft hyphens and variation selectors
Soft hyphens suggest wrap points. Variation selectors affect character rendering. The tool reports and removes supported characters in these groups.
An invisible character is not automatically malicious and is not evidence of AI generation.
Frequently asked questions
Why do hidden characters appear?
They can come from ordinary editors, websites, formatting systems, conversions, or automated tools.
Do they prove AI authorship?
No. They also occur in human-created documents and ordinary software.
Is removal private?
Yes. UnmarkAI processes the pasted text locally in your browser.