Structured text (Stx) is a kind of plaintext with unambiguous markup for formatting constructs. It is designed to adhere to the tradition and readability of plaintext, with _emphasis_ marked by underscores, paragraph breaks by empty lines, and so on.

Stx is meant to be as good an authoring format as possible. It combines the benefits of structured markup (mid-level semantic markup such as DocBook or HTML) with the ease and readability of plaintext.