How Base64 Encoding Works

Break down the Base64 alphabet, padding rules, and byte groups so every conversion makes sense.

Base64 encoding takes binary data and splits it into 24-bit groups. Each group is divided into four 6-bit values which map to characters from the Base64 alphabet. Because the alphabet contains only URL-safe and ASCII-printable characters, the result travels safely through systems that cannot handle raw binary.

When the original data does not divide evenly into 24-bit chunks, padding characters are added. The equals sign (=) fills the missing bytes so that decoders can reconstruct the exact bit pattern. Understanding this padding makes it easier to spot when a string is truncated or when extra characters have been introduced.

Armed with this knowledge, you can use Base64decode to inspect tokens, debug API payloads, or embed assets in configuration files without guessing what the encoded data represents.