tocncx

tocncx is a command-line utility designed to generate a Navigation Control file for XML (NCX) from a book’s table of contents for EPUB 2 publications. The NCX file describes the reading order and navigation points that help readers move through a book, and it remains a key component in many e-book production workflows for compatibility with older EPUB 2 devices and readers.

Typically, tocncx accepts a table of contents in formats such as JSON, YAML, or a plain-text outline, and outputs an NCX document that conforms to the EPUB 2 specification. It assigns unique identifiers to each navPoint, preserves nesting levels for chapters and sections, and can include metadata like titles and languages. The tool is designed to produce a structurally correct navMap with proper playOrder sequencing.

Usage of tocncx is common in workflows alongside other e-book tools such as Pandoc or Calibre. A typical invocation might specify an input TOC file and an output NCX file, for example: tocncx -i toc.json -o toc.ncx. The goal is to simplify the creation of valid NCX files for authors and publishers who need NCX compatibility within their EPUB 2 pipelines.

Availability and status: tocncx appears as a niche project with limited public documentation. It may be distributed as a standalone binary or as source code on code hosting platforms, with varying levels of maintenance across forks. Because EPUB 3 uses a different navigation model, NCX support is primarily relevant for legacy EPUB 2 workflows or mixed-format publications.

See also: NCX, EPUB, Table of contents, EPUB 2, EPUB 3, e-book production tools.