Base64 Encoder & Decoder

The Base64 Encoder & Decoder is a privacy-first, client-side tool for converting plain text, UTF-8 strings (including full Unicode and Khmer script), and binary file content (images, PDFs) into their Base64 ASCII representation and back. Base64 encoding (defined in RFC 4648) is a binary-to-text encoding scheme that represents binary data using 64 printable ASCII characters (A–Z, a–z, 0–9, +, /), making it safe to embed binary payloads inside text-only channels such as JSON request bodies, XML documents, CSS data URIs, and email MIME attachments. This tool handles the full UTF-8 byte encoding pipeline required for non-ASCII characters, a step that many competing online encoders incorrectly omit, producing garbled output for Khmer, Chinese, or Arabic input.

Algorithmic Logic & Calculation

For text encoding, the tool first encodes the input string as a UTF-8 byte array using TextEncoder, then converts each byte to a binary string with String.fromCharCode(), and finally applies btoa() to generate the Base64 output. This three-stage pipeline ensures Khmer characters (multi-byte in UTF-8) are correctly represented. For decoding, atob() reverses the Base64 to a binary string, Uint8Array captures each byte code, and TextDecoder reconstructs the original UTF-8 string. For image/file encoding, the FileReader API reads the file as a DataURL, which is natively Base64-encoded.