Base64 turns binary data into plain text using 64 URL-safe characters. It is often used to inline small images in CSS, embed attachments in emails, or move data through text-only systems.

Encoding increases size by about 33%, so avoid it for large assets. Never treat Base64 as encryption—it is reversible and provides no security.

Use it when transport constraints require text-only payloads, and decode on the receiving side before processing.