Programming Terminology


Related to: ASCII, String

When a file or data is referred to as "plaintext", it means the contents are human-readable using regular characters you would find on a keyboard. For example, HTML, CSS, and JavaScript are plaintext files. Pretty much all source code is plaintext because humans are the ones writing it. If you don't know code yet, you might not understand what's going on with the syntax, but you will recognize all the characters like in this bit of JavaScript code:

const firstNames = ['Brian Hanson', 'Ashley Rodriguez'].map(n => n.split(' ')[1])

The contents of some file formats are created by computers and not humans, so they might be encoded or encrypted like the first few characters of a JPEG image that might look like this:


A more technical definition can be found at Wikipedia where they describe plaintext as being "unencrypted information" and that "can be viewed or used without requiring a key or other decryption device".

Sometimes non-plaintext data (like the image content above) uses computer characters that don't have a visual representation that we would recognize, thus the computer represents them as these strange looking question marks we see in the encoded image contents above.