Every character TraceFree PRO knows
What each one is, where it comes from, and — the part most tools skip — when it belongs exactly where it is.
control-char
The non-printing control codes inherited from teleprinters and terminals: bell, form feed, escape, delete and their relatives, plus a second block that arrived with the 8-bit character sets.
space-variant
Spaces that are not the ordinary space: some prevent a line break at that point, some have a fixed width regardless of the font, some do both. They are visible as whitespace but indistinguishable by eye from a normal space.
smart-quotes
Typographic quotation marks and their relatives: the curved opening and closing forms, the low forms German uses, and the angled guillemets of French and several other languages.
soft-hyphen
An invisible hint that says a hyphen may be drawn here if the line has to break. When the line does not break there, nothing is shown at all.
bidi-control
Bidirectional controls tell the text renderer which direction a run of characters should be laid out in. They are invisible and they change nothing about the stored text — only about how it is drawn.
zero-width
A zero-width character takes up no space and draws no glyph. In an editor the cursor steps over it and nothing moves; in a text field the line looks exactly as it would without it. It is nevertheless a character, stored in the file and counted by every length function.
joiner
Two invisible characters that control whether the glyphs around them join: one forces a connection, the other prevents one. They are zero-width, and they carry meaning.
dashes
The dashes that are not the ASCII hyphen-minus: the en dash of ranges, the em dash of interruptions, the true minus sign of mathematics, and the non-breaking hyphen.
ellipsis
Three dots as a single character, with the spacing between them set by the font rather than by three separate periods.
line-separator
Unicode's own line and paragraph breaks, separate from the line feed and carriage return inherited from ASCII. They mean the same thing and are handled correctly by far fewer programs.
variation-selector
Invisible characters that pick between two shapes of the character before them. The best-known pair chooses whether a symbol is drawn as flat black-and-white text or as a colour emoji.
replacement-char
The visible tombstone of a character that was lost. A decoder that meets a byte sequence it cannot interpret puts this in its place, so the failure is recorded rather than silently swallowed.
tag-characters
A block of 128 codepoints that mirror printable ASCII and render as absolutely nothing. They were introduced for language tagging, that use was deprecated, and what remains is a complete invisible alphabet.
homoglyph
Each character is perfectly correct in its own script. There is nothing wrong with a Cyrillic a in a Russian word.
TraceFree PRO therefore reports these only inside words that mix scripts, and never in single-script text. That restraint is deliberate: a false positive here costs more trust than a missed detection.
Compare the two editions
| Feature | PRO * | FREE * |
|---|---|---|
| All 516 characters the engine knows | Yes | Yes |
| Context guards: emoji, Arabic and Indic scripts, CJK stay intact | Yes | Yes |
| Bidirectional controls (“Trojan Source”) | Yes | Yes |
| Homoglyphs inside mixed-script words | Yes | Yes |
| Watch the clipboard | Yes | Yes |
| Before-and-after comparison before any change | Yes | Yes |
| Four rule sets: default, conservative, strict, report only | Yes | Yes |
| Interface in 20 languages | Yes | Yes |
| No account, no network access | Yes | Yes |
| Automatic mode: clean quietly, without asking | Yes | – |
| Watch folders and clean text files, with backups | Yes | – |
| Rules of your own for individual characters | Yes | – |
* Moving from FREE to PRO is a one-time in-app purchase, not a subscription.
Try it on your own text
Paste anything into the browser demo and see what is in it. Same engine as the app, running entirely on your device — nothing is uploaded.
