Rea Language

Rea is a plain-text markup language for interactive stories. Its defining property is that plain text is already a valid Rea document — an ordinary paragraph of prose is a complete, renderable story. Formatting, choices, variables, logic, multimedia, cooperative reading and real-world interaction are all opt-in additions layered on top of prose. Nothing is required; you reach for syntax only when you need it.

Rea exists for branching narrative that a person can write in a text editor and diff in git, and that a machine can validate, render and sandbox. The same file is readable by a human and executable by the engine — there is no separate compiled form.

The three stages below are all valid Rea. The first line is already a complete story; the second adds one variable, the third one choice:

The road forked at the old oak.

{set player.torch = true}

* [Take the left path]
* [Take the right path]

File types

• .rea — a story file: prose plus any opt-in Rea syntax.
• .rext — a Rea extension module: declaration-only (functions, top-level {set} constants, {use} and comments — no prose). See When rules differ in .rext files.
• .reast — the distributable ZIP package: one or more .rea files, optional .rext extensions and media, plus a manifest.json. See the engine's .reast package format reference.

What Rea is not

Rea is not a general-purpose programming language, not HTML and not a game engine. Its functions are sandboxed and intentionally limited, its rendering is platform-controlled, and it has no raw markup passthrough. For the full list of deliberate exclusions, see What Rea intentionally omits.

Reading order

The specification is split into five parts, meant to be read in order the first time through:

1. Basics — document structure, text formatting, headings, links, media, anchors, and choices.
2. Logic & Data — commands, variables, expressions, and control flow.
3. Narrative & Interaction — dialogue, cards, voice, input, cooperative reading, and real-world interactions.
4. Utilities — pluralization, localization, content protection, captions, and error handling.
5. Reference — identifiers, built-in functions, extensibility, accessibility, and conformance levels.

Looking for a quick syntax refresher instead of the full spec? See the Cheatsheet.