This Base64 encoder and decoder is built for web developers and system engineers who deal with Base64 conversions across HTTP request headers, email attachments (MIME), Data URI Schemes, JWT tokens, and API authentication. Base64 (RFC 4648) converts 8-bit binary data into a 64-character ASCII alphabet (A–Z, a–z, 0–9, +, /) so that binary information can travel through text-only protocols without corruption. Critically, this tool is built to handle UTF-8 Unicode correctly—including Korean Hangul, emoji, Chinese, Japanese, and multi-byte characters—eliminating the Latin1 limitation and character corruption bugs found in the browser's native btoa()/atob() functions. Note that Base64 inflates payload size by about 33% (4/3 ratio), making it unsuitable for large binary transfers, and it is encoding, not encryption—anyone can decode it, so never use Base64 to protect passwords or sensitive data. All conversions run entirely in your browser with zero server transmission, guaranteeing complete privacy.