Text reverser

Reversing text is useful more often than you might think: checking palindromes, reversing the order of log lines so the newest appear first, flipping a list, creating puzzles, or testing how your code handles Unicode. This tool reverses text in three ways: by characters, by words or by lines.

How to use it

1. Paste or type your text.
2. Choose the mode: characters, words or lines.
3. Copy the result.

Examples

• Characters: Hello world becomes dlrow olleH.
• Words: one two three becomes three two one.
• Lines: a list of log entries from oldest to newest becomes newest to oldest, with each line unchanged.

The Unicode trap

A naive reverse in JavaScript, str.split('').reverse().join(''), works on UTF-16 code units, not characters. It breaks emoji and other characters outside the Basic Multilingual Plane into invalid halves, and separates accents written as combining marks from their letters. Reversing café 👍 that way can produce garbage. A correct approach splits text into grapheme clusters, the characters a user actually sees, for example with Intl.Segmenter.

Practical uses

• Palindrome checks: lowercase the text, remove spaces and punctuation, then compare it with its reverse. A man, a plan, a canal: Panama passes.
• Reversing lists exported in the wrong order.
• Command-line equivalents: rev reverses characters on each line and tac reverses line order.