Base64
termprogrammingweb dev
An encoding that represents arbitrary bytes using 64 printable characters, so binary data can travel through channels that only accept text.
It is not encryption and not compression: it makes data larger, by roughly a third, in exchange for surviving transports that would mangle raw bytes. The reason it is everywhere is historical - email was text-only, and everything built on that assumption inherited the need. Two practical notes: the URL-safe variant exists because plus and slash mean something in a URL, and seeing Base64 in a payload tells you nothing about whether the content is safe, which is why decoders belong in every analyst's toolkit rather than in their conclusions.
Also known as: base64url