Base64 Encoder / Decoder

Base64 is a binary-to-text encoding scheme that translates raw binary coordinates or complex character sets into a restricted index of 64 standard ASCII symbols. It is commonly used to transmit binary structures safely over systems designed purely to handle plain text, such as XML documents, email systems, and JSON APIs. If you are formatting duplicate variable lists before encoding them, you can filter unique entries with our Duplicate Line Remover. Here is how a plain text string maps to its corresponding Base64 equivalent:

// Plain Text String
"Hello World"

// Base64 Encoded Equivalent
"SGVsbG8gV29ybGQ="

Standard encoding takes three 8-bit bytes (24 bits total) and splits them into four 6-bit chunks, mapping each chunk to the standard Base64 index. If the input text length isn't divisible by three, equals signs (=) are appended to pad the string. If your encoded outputs are destined for web browser search queries, make sure they are url-safe using our URL Encoder / Decoder. Here is a simple JavaScript function to encode standard strings:

function encodeStringToBase64(str) {
  const bytes = new TextEncoder().encode(str);
  const binString = Array.from(bytes, (byte) => String.fromCodePoint(byte)).join("");
  return btoa(binString);
}

Decoding reverses the process, reconstructing the original 8-bit binary octets from the 6-bit Base64 indexes. If the decoded output resolves to a structured JSON payload, you can easily pretty-print the layout using our visual JSON Formatter & Validator. Here is the robust JavaScript decoding helper:

function decodeBase64ToString(base64Str) {
  const binString = atob(base64Str);
  const bytes = Uint8Array.from(binString, (m) => m.codePointAt(0));
  return new TextDecoder().decode(bytes);
}

Base64 is a fundamental component of web development, appearing in headers, tokens, and data channels. It is the standard mechanism for transmitting credentials in HTTP Basic Access Authentication, as well as the structure behind JWT tokens. If you are decoding JWT payloads to verify claim objects, inspect variables with our interactive JWT Decoder. Here is how a basic authorization header is structured:

Authorization: Basic dXNlcm5hbWU6cGFzc3dvcmQ=

// Decodes back to -> "username:password"

Data URIs allow designers to embed small files, such as raster PNGs or vector favicons, directly inside HTML markups or stylesheets to save HTTP requests. If you are generating custom browser icons for your site, try our online Favicon Generator. Here is a typical CSS background style sheet using a Base64 data URI:

.icon-box {
  background-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9h...");
  width: 16px;
  height: 16px;
}

Standard browser tools like window.btoa and window.atob fail on high-code-point UTF-8 characters (like emojis or international scripts). Our tool implements a robust encoding conversion layer that pre-processes text variables into multi-byte octets, ensuring that emojis remain fully preserved:

// standard btoa("🚀") throws a DOMException
// Our UTF-8 utility converts it safely to -> "8J+Zhg=="