Character Inspector

Why text misbehaves

Two strings can look identical on screen and be completely different to a computer. Text copied out of a word processor, a PDF, a chat client or a web page routinely picks up characters that are invisible, or that merely resemble the ones you meant. The result is a password that won't match, a search that finds nothing, a CSV that won't parse, or code that throws a syntax error on a line that looks perfect.

The usual suspects

• Zero-width characters. Zero-width space, joiner, non-joiner and the byte-order mark occupy no visual space at all. They survive copy and paste, and they are also how invisible watermarks are hidden in shared text.
• Non-breaking spaces. Look exactly like a normal space, aren't one. A classic cause of "this looks the same but doesn't match".
• Smart quotes and dashes. Word processors silently convert " to curly quotes and -- to an em dash. Paste that into code or a terminal and it breaks.
• Lookalike letters. A Cyrillic а is not a Latin a, though they render identically in most fonts. This is the basis of homograph phishing domains, and it turns up accidentally in text pasted from mixed sources.
• Control characters. Stray bytes below the printable range, usually picked up from a badly decoded file. They are invisible and break parsers.

What "clean it up" does

It removes zero-width characters entirely, converts non-breaking and other exotic spaces to ordinary spaces, straightens curly quotes and dashes, and strips trailing whitespace from each line. It leaves accented letters, emoji and non-Latin scripts alone — those are usually intentional. Lookalike letters are reported but never silently swapped, because guessing at intent there would do more harm than good.

One thing this can't check

Line endings. Browsers normalise carriage returns out of every text box before script can see them, so a CRLF file pasted here arrives already converted — there is no way to tell from inside the page whether the original used Windows or Unix endings. Anything claiming otherwise in a browser text box is guessing. Use file on macOS or Linux, or open the file in an editor that shows line endings in its status bar.

Nothing leaves your browser

All of this runs locally. The text is never sent anywhere, which matters given that the things people most need to inspect are passwords, keys and pasted credentials.