Base64

In JavaScript (and with the window object), the respective functions for base 64 handling are btoa() and atob().

Base64 is used in the Basic HTTP authentication scheme to transmit user-id/password pairs (see RFC-7617).

Base64 is described in RFC 4648

Encoding and decoding base 64 with c++

On a Windows command line, certutil -decode and certutil -decode provide a possibility to encode/decode a file in base 64 if no tool can be installed.

On Linux, there is the base64 utility.

java.util.Base64

Perl module MIME::Base64

MIME

Using data URIs (<img src="data:…, ">) in HTML to embed (usually binary data) data (encoded in Base64) within the HTML document itself.