A palindrome is a word, phrase, number, or sequence of characters that reads the same forward and backward, ignoring spaces, punctuation, and capitalization. Common examples include "radar", "level", and "A man, a plan, a canal, Panama!".

The tool processes your input according to your selected options: it optionally converts text to lowercase, removes accents (diacritics), and strips all non-alphanumeric characters. Then it compares the resulting string with its reversed version. The visual comparison instantly shows you which characters match or differ.

• "A man, a plan, a canal, Panama!"
• "Never odd or even."
• "Madam, in Eden, I'm Adam."
• "Race fast, safe car."
• "Do geese see God?"
• "Was it a car or a cat I saw?"

By default, the tester ignores spaces, punctuation, and other non-alphanumeric characters (option "Ignore Punctuation & Spaces" is checked). You can uncheck that option if you want punctuation and spaces to be part of the palindrome comparison. For example, "racecar" is a palindrome, but with spaces "race car" is still considered one when ignored.

With the "Ignore Case" option enabled (default), the checker converts all letters to lowercase before comparison. This means "Racecar" and "RACECAR" are both considered palindromes. Disabling this option requires exact case matching, so "RacecaR" would be valid but "Racecar" would not.

Yes, numeric palindromes are common. Examples: 121, 12321, and 1991. Dates like 02/02/2020 (when written without slashes) also form palindromes. This tool treats numbers the same as letters, so "12321" will be identified as a palindrome.

When the "Ignore Accents" option is enabled, the tool normalizes accented characters to their base form (e.g., "é" becomes "e", "ñ" becomes "n"). This allows phrases like "Noël, I saw Leon!" to be recognized as a palindrome. Disable the option if you need strict diacritic matching.

"Tattarrattat" (meaning a knock on the door in James Joyce's Ulysses) is often cited as the longest palindromic word in English. Some place names, such as the Finnish "Saippuakivikauppias" (soapstone vendor), are even longer.

Absolutely. The tool visually demonstrates the cleaned and reversed strings, which matches the standard algorithm used in coding interviews: normalizing and comparing a string to its reverse. It's a great way to verify your own palindrome-checking code.

Palindromes appear in recreational linguistics, wordplay, and biological sequences (DNA). In computer science, palindrome detection is a classic string manipulation problem that introduces concepts like two-pointer technique and recursion. They're also culturally significant as symmetrical patterns.