RSt

reStructuredText, commonly abbreviated as reST or rst, is a lightweight plaintext markup language designed for documentation. Its syntax is crafted to be readable in source form while enabling conversion to rich output formats such as HTML, LaTeX, and XML.

RST originated within the Docutils project and was developed in the early 2000s by David Goodger. It was created to provide a flexible, extensible markup that could be parsed into multiple target formats. The Python ecosystem adopted it widely, most notably through the Sphinx documentation generator, which relies on reStructuredText for project documentation and API references.

The language uses simple punctuation-based constructs to convey structure and formatting. Section headings are indicated by underlines (and optional overlines) made of characters like =, -, ~, ^, or ". Other features include bullet and enumerated lists, emphasis and strong text, literals for code blocks, and inline roles and directives for notes, admonitions, and references. It also supports hyperlinks, footnotes, citations, tables, and substitution definitions. Extensions and custom directives allow additional blocks and semantics, enabling project-specific documentation conventions.

Core tooling centers on Docutils, which can convert .rst files to HTML, LaTeX, XML, and other formats. Sphinx adds further capabilities for Python projects, including advanced cross-referencing, API documentation, and theming. The .rst file extension is common in Python projects and is supported by many editors and IDEs.

Compared with Markdown, reStructuredText offers richer semantics and tooling for technical documentation, at the cost of a steeper learning curve and a more opinionated ecosystem.