Base64 encoder / decoder

Paste or type your text and it converts instantly. Encode mode turns any text into standard Base64 (UTF-8-safe, so emoji and CJK characters round-trip correctly), and Decode mode turns a Base64 string back into readable text, accepting both the standard and URL-safe alphabets with or without padding. Invalid input shows a friendly error instead of breaking the page, and the URL-safe option produces - and _ alphabet output with padding removed.