Ydown

Ydown is a lightweight markup language designed for writing documentation and notes. It aims to be an approachable alternative to Markdown, emphasizing readability in the raw source and straightforward conversion to HTML, PDF, and ePub.

Originating as an open-source project developed by a global community of contributors, Ydown was released in its early form in the mid-2010s and has since matured through several minor releases to a stable 1.x line.

Ydown provides support for common document elements, including headings, paragraphs, emphasis, strong text, lists, code blocks, links, images, and tables. It also offers built-in support for footnotes and callouts, with a focus on predictable parsing and minimal ambiguity.

The syntax is purposely compact and readable in plain text. Markup tokens are designed to be easy to remember and forgiving of minor formatting variations, while preserving a consistent structure when rendered to other formats.

Several reference implementations and libraries exist in JavaScript, Python, and Rust, along with tools that integrate Ydown into static-site generators and documentation workflows. The ecosystem emphasizes portability, with round-trip conversion between Ydown and common output formats.

Adoption remains modest relative to Markdown, with usage concentrated in certain open-source projects and technical documentation communities. Support and tooling have improved, but the ecosystem is smaller, and some users cite a thinner plugin and theme ecosystem.

See also: Markdown, reStructuredText, AsciiDoc.