テキストをBase64にエンコード、またはデコードして元のテキストに戻す
Our free Base64 encoder and decoder lets you instantly convert text to Base64 encoding or decode Base64 back to readable text. Base64 encoding is widely used for data transmission over media designed to handle textual data — including email attachments via MIME, storing complex data in JSON or XML, embedding images in HTML/CSS, and authentication headers in HTTP.
Whether you're a developer debugging API payloads, a security researcher analyzing encoded data, or a student learning about encoding schemes, our tool makes it trivial to encode and decode. All processing happens locally in your browser — your data never touches any server. This tool supports UTF-8 characters and handles errors gracefully when decoding invalid Base64 strings.