Palindrome checker

Test whether text reads the same backwards — letter-only and exact modes, with the longest palindrome found.

Checked in this browser. Nothing is sent anywhere.

Unicode NFKC + case-fold, combining marks and punctuation stripped, then compared against its reversal — accents, case, and spacing don't count. ASCII letters/digits only after normalization, so kana or Cyrillic are dropped.

How to use

  1. Paste text.
  2. Choose strict or letters-only comparison.
  3. Read the verdict and the longest palindrome inside.

What it supports

Letters-only mode strips punctuation, spaces, accents (Unicode NFD), and case before comparing — 'A man, a plan, a canal: Panama' passes. Strict mode compares character-for-character. Also finds the longest palindromic substring. Up to 200,000 characters.

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