Mime Encoder

Encodes and decodes text using the two main MIME transfer encodings used in email headers and bodies: Base64 and Quoted-Printable. Base64 mode is UTF-8 aware (it round-trips non-ASCII through encodeURIComponent), while Quoted-Printable escapes any byte outside the printable ASCII range as =XX hex and soft-wraps lines at 76 characters.

1. Choose the operation mode: Encode or Decode. 2. Choose the encoding: base64 or quotedPrintable. 3. Type or paste your text into the input card. 4. Click the Encode/Decode button. The output card appears with the result. 5. Use Copy to copy or Download to save it as a .txt file (named mime-encoded-base64.txt or similar). Invalid input on decode shows an error banner.

Base64 encode uses UTF-8 safe encoding so emoji and CJK characters survive a round trip; Base64 decode reverses it and throws on invalid Base64. Quoted-Printable encode marks bytes below 32, above 126, or the = byte (ASCII 61) as =XX, and inserts =\r\n soft line breaks before exceeding 76 columns. Quoted-Printable decode first strips =\r\n soft breaks, then resolves every =XX sequence back to its raw byte before UTF-8 decoding.