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Hidden Character Detector and Cleaner
Find invisible characters such as zero-width spaces, non-breaking spaces and smart quotes, then strip them out.
What is Hidden Character Detector and Cleaner?
Some characters never appear on screen yet still sit inside your string. The most common are zero-width spaces, non-breaking spaces, byte order marks and soft hyphens. They arrive when you copy from Word, Google Docs, a web page or a chat message.
The consequences are maddeningly hard to trace: pasted code fails to run despite looking identical, two apparently matching strings compare as different, a pasted password is rejected, or a domain name displays correctly but leads somewhere else. You can stare at it for hours and see nothing wrong.
More pointedly, invisible characters are also used to fingerprint text. The same document sent to several people, each copy carrying a different zero-width sequence — when the content leaks, the sender knows exactly who leaked it. This tool shows you everything hiding in your text.
How to use
- Paste the text you want checked into the box above.
- If hidden characters are present, the table below lists each type with its Unicode code point, occurrence count and positions.
- Review the cleaned text at the bottom.
- Click Copy to take the clean version.
Frequently asked questions
Where do hidden characters come from?
Mostly from copying. Word and Google Docs convert straight quotes to curly ones and hyphens to en dashes. Web pages insert zero-width spaces to control line breaking. Files exported from older systems often carry a byte order mark at the start.
Why do they break code?
Because a compiler reads bytes, not shapes. A curly quote is not a straight quote; a non-breaking space is not a space. Your eyes see the same thing, the machine sees something entirely different.
What exactly does the cleaner do?
It removes zero-width and control characters outright, converts special spaces to ordinary spaces, and converts curly quotes and long dashes to their ASCII equivalents.
Is text fingerprinting with invisible characters real?
Yes, and the technique is fairly common for tracing document leaks. Since the characters are entirely invisible, inserting a few distinct sequences is enough to give every copy its own identifier.