Base64 / URL / Hex 変換

プレーンテキスト、Base64、URL エンコード、16 進数を相互変換。リアルタイム、完全ローカル、UTF-8 を正しく処理。

When you need to quickly Base64-encode a token, URL-encode a query string, or peek at the raw hex bytes of a snippet — open the popup, paste, and read the result. Everything happens inside your browser; no network requests, no analytics, no log files. Key features: - Three codecs in one popup: Base64, URL-encoding (percent-encoding), and Hex - One-click swap between Encode and Decode for the selected codec - Live transform — the output updates as you type, with no "Run" button to remember - Correct UTF-8 handling for non-ASCII text (Chinese, emoji, etc.) in every codec - Inline error indicator when the input is not valid for the selected codec - One-click copy on the output; tab + direction preference is remembered locally No data leaves your device. The codecs run entirely on your machine using built-in browser primitives.