Reverse Text

What this tool does

It reverses text — by characters, by words, or by lines — and it does so correctly for Unicode, which is less trivial than it sounds. Reversing a string is the standard example of a task that looks like a one-liner and turns out to have real depth once you leave plain ASCII.

The three modes

Word reversal keeps each word intact and reverses their order, which is what you want for reordering a list. Line reversal is useful for flipping chronological logs, changelogs or any file where the newest entry sits at the bottom.

Why naive reversal breaks

The obvious approach — split a string into its code units and reverse the array — produces mangled output for a large fraction of the world's text.

• Emoji and astral characters. Characters above U+FFFF are stored as two 16-bit surrogate code units in JavaScript. Reversing blindly separates the pair and produces invalid characters.
• Combining marks. An accented letter may be stored as a base letter followed by a combining accent. Reversing puts the accent before the letter, so it attaches to the wrong character.
• Emoji sequences. Family emoji, skin-tone modifiers and flags are several code points joined by zero-width joiners. Reversing scrambles them into unrelated symbols.
• Indic and Thai scripts use combining vowel signs whose position relative to the consonant is meaningful, so reversal destroys the syllable structure.

The correct unit to reverse is the grapheme cluster — what a reader perceives as one character — rather than the code unit or even the code point. This tool works at that level, so emoji, accents and joined sequences survive intact.

Right-to-left text

Arabic and Hebrew are written right to left, but they are stored in logical order — the order you would read them aloud. The browser handles the visual direction. This means reversing Arabic text does not produce readable Arabic backwards; it produces logically reversed text that the display engine then lays out, usually to confusing effect. If you want the visual appearance of reversed text in an RTL script, direction is a rendering property, not something to achieve by reordering characters.

What people use it for

• Checking palindromes — reverse and compare. Note that a proper palindrome check ignores case, spaces and punctuation, so "A man, a plan, a canal: Panama" qualifies.
• Reversing log files so the newest entries appear first.
• Puzzles, word games and cryptic clues.
• Testing text handling in software — reversed emoji and combining marks are excellent for finding encoding bugs.
• Creating mirrored text for design work, though a true mirror image needs a CSS transform rather than character reversal, since letters like b and d do not become each other by reordering.

A note on obfuscation

Reversed text is sometimes used to slip past keyword filters or to hide content from casual readers. It offers no real protection — reversing is trivially undone, as this page demonstrates — and moderation systems normalise text before matching in any case. Treat it as a novelty, not a technique.

Runs entirely in your browser

The reversal happens locally in JavaScript. Nothing is uploaded, so pasting confidential text carries no transmission risk. Very long inputs are handled without difficulty, since the operation is linear in the length of the text.

Frequently asked questions