@apexmarkdown/apex

Fast, synchronous Markdown conversion for Node.js using the native Apex engine. Apex combines CommonMark, GitHub Flavored Markdown, MultiMarkdown, Kramdown, Quarto, and dozens of opt-in extensions behind one API.

Quick start

Install the package:

npm install @apexmarkdown/apex

Convert Markdown with CommonJS:

const { convert } = require("@apexmarkdown/apex");

const html = convert("# Hello\n\nThis is **Apex**.");
console.log(html);

Or with an ES module:

import apex from "@apexmarkdown/apex";

const html = apex.convert("# Hello\n\nThis is **Apex**.");

Both examples return:

<h1 id="hello">Hello</h1>
<p>This is <strong>Apex</strong>.</p>

By default Apex reports unified with a broad feature set. Pass an explicit mode when matching another Markdown processor, or when you want citations and indices enabled:

const { convert } = require("@apexmarkdown/apex");

const html = convert(markdown, {
  mode: "gfm",
  unsafe: false
});

Why Apex?

• One processor for CommonMark, GFM, MultiMarkdown, Kramdown, Quarto, and Apex's combined unified mode.
• Tables, footnotes, definition lists, attributes, callouts, math, Critic Markup, citations, wiki links, file includes, and more.
• HTML, normalized Markdown, JSON AST, terminal, man page, and TOC output.
• Native prebuilt binaries with no system cmark-gfm or libyaml installation.
• Bundled TypeScript declarations.

See the Apex syntax guide and mode comparison for the supported Markdown syntax.

Common recipes

GitHub Flavored Markdown

const html = convert(markdown, { mode: "gfm" });

GFM mode enables tables, task lists, strikethrough, and autolinks while using conservative raw-HTML handling.

Enable selected extensions

Options override the defaults selected by mode:

const html = convert(markdown, {
  mode: "commonmark",
  enableTables: true,
  enableFootnotes: true,
  enableCallouts: true
});

Create a complete HTML document

const document = convert(markdown, {
  standalone: true,
  documentTitle: "Release notes",
  stylesheetPaths: ["./site.css"],
  pretty: true
});

Render for a terminal

const output = convert(markdown, {
  outputFormat: "terminal256",
  terminalWidth: 100,
  themeName: "dark"
});

API

convert(markdown, options?)

Synchronously converts a Markdown string and returns a string in the selected output format.

function convert(markdown: string, options?: ApexOptions): string;

markdown must be a string. options must be an object whose own properties are documented below. Unknown options, invalid enum values, wrong value types, non-finite numbers, fractional integers, and integers outside the signed 32-bit range throw a TypeError. A native conversion failure throws an Error.

version

A string containing the bundled Apex engine version:

const { version } = require("@apexmarkdown/apex");
console.log(version); // for example, "1.1.12"

version is a string, not a function.

TypeScript

The package includes declarations for convert, version, ApexOptions, and every string union used by the API:

import type { ApexOptions } from "@apexmarkdown/apex";

const apex: typeof import("@apexmarkdown/apex") =
  require("@apexmarkdown/apex");

const options: ApexOptions = {
  mode: "gfm",
  generateHeaderIds: true
};

const html = apex.convert("# Typed", options);

Modes and defaults

mode selects a complete set of defaults first. Every other supplied option then overrides that set.

• commonmark — strict CommonMark with most extensions disabled.
• gfm — GitHub tables, task lists, strikethrough, and autolinks.
• multimarkdown — MultiMarkdown metadata, tables, footnotes, includes, definition lists, math, and citations.
• kramdown — Kramdown-compatible attributes, footnotes, definition lists, and related syntax.
• unified — Apex's combined feature set, including citations and indices.
• quarto — Quarto-oriented parsing and extensions.

If mode is omitted, Apex starts from its no-mode defaults, which report unified but leave citations and index processing disabled. Pass mode: "unified" when you want citations and indices enabled by default.

Defaults otherwise vary by mode. The descriptions below explain each override rather than claiming one value across every mode.

Complete option reference

All option names are camelCase and case-sensitive.

Parser modes and feature sets

• mode ("commonmark" | "gfm" | "multimarkdown" | "kramdown" | "unified" | "quarto") — Select the base parser mode and its defaults.
• enableTables (boolean) — Enable pipe tables.
• enableFootnotes (boolean) — Enable reference and inline footnotes.
• enableDefinitionLists (boolean) — Enable definition-list syntax.
• enableSmartTypography (boolean) — Convert quotes, dashes, ellipses, and related punctuation.
• enableMath (boolean) — Enable inline and display math syntax.
• enableCriticMarkup (boolean) — Parse Critic Markup additions, deletions, substitutions, highlights, and comments.
• enableWikiLinks (boolean) — Parse [[wiki links]].
• enableTaskLists (boolean) — Enable GFM task-list checkboxes.
• enableAttributes (boolean) — Enable inline attribute lists and related attribute syntax.
• enableCallouts (boolean) — Enable Bear/Obsidian > [!TYPE] callouts.
• enablePyCallouts (boolean) — Enable Python-Markdown !!! callouts.
• enableQuartoCallouts (boolean) — Enable Quarto callout blocks.
• enableQuartoExtensions (boolean) — Enable the general Quarto extension set.
• enableQuartoRaw (boolean) — Enable Quarto raw-content blocks.
• enableQuartoExampleLists (boolean) — Enable Quarto example lists.
• enableQuartoLineBlocks (boolean) — Enable Quarto line blocks.
• enableQuartoRomanLists (boolean) — Enable Quarto Roman-numeral lists.
• enableQuartoCodeAttrs (boolean) — Enable Quarto code-block attributes.
• enableQuartoDiagrams (boolean) — Enable Quarto diagram handling.
• enableQuartoShortcodes (boolean) — Enable Quarto shortcodes.
• enableQuartoStrictLists (boolean) — Use Quarto's stricter list parsing.
• enableQuartoXrefs (boolean) — Enable Quarto cross-references.
• enableMarkedExtensions (boolean) — Enable Apex's Marked-compatible extensions.
• enableDivs (boolean) — Enable fenced divs.
• enableSpans (boolean) — Enable bracketed spans with attributes.
• enableGridTables (boolean) — Enable Pandoc-style grid tables.

Plugins

• enablePlugins (boolean) — Run Apex plugin processing.
• allowExternalPluginDetection (boolean) — Allow discovery of external plugins.

Plugins can execute external code. Enable them only when the installed plugins and input are trusted.

Critic Markup

• criticMode ("markup" | "accept" | "reject") — Preserve Critic Markup, accept all tracked changes, or reject them.

Metadata and file inclusion

• stripMetadata (boolean) — Remove parsed metadata blocks from rendered content.
• enableMetadataVariables (boolean) — Expand metadata variables such as [%key].
• enableMetadataTransforms (boolean) — Enable transforms in metadata-variable expressions.
• enableFileIncludes (boolean) — Resolve Apex, MultiMarkdown, and compatible file-include syntax.
• maxIncludeDepth (number) — Set the maximum recursive include depth as a signed 32-bit integer.
• baseDirectory (string) — Resolve relative includes and file-backed resources from this directory.
• inputFilePath (string) — Supply the source path exposed to plugins and path-aware processing.

File includes and file-backed options can read local files. Set baseDirectory deliberately when converting untrusted input.

Output

• outputFormat ("html" | "json" | "jsonFiltered" | "markdown" | "mmd" | "commonmark" | "kramdown" | "gfm" | "terminal" | "terminal256" | "man" | "manHtml" | "toc") — Select the returned representation.
• unsafe (boolean) — Allow raw HTML instead of applying cmark's safe-HTML handling.
• validateUtf8 (boolean) — Replace invalid UTF-8 sequences with the Unicode replacement character.
• githubPreLang (boolean) — Put fenced-code languages on <pre lang="..."> in GitHub style.
• standalone (boolean) — Emit a complete document instead of a fragment.
• pretty (boolean) — Pretty-print generated HTML.
• xhtml (boolean) — Render void elements using XHTML syntax.
• strictXhtml (boolean) — Use stricter polyglot XHTML scaffolding for standalone output.
• stylesheetPaths (string[]) — Add stylesheet paths to standalone output.
• documentTitle (string) — Set the standalone document title.

unified mode permits raw HTML by default, while strict compatibility modes may not. Set unsafe: false explicitly when processing untrusted Markdown that must not pass raw HTML through.

Terminal rendering

• themeName (string) — Select the terminal rendering theme.
• terminalWidth (number) — Set the terminal width as a signed 32-bit integer; 0 lets Apex determine it.
• paginate (boolean) — Mark terminal output for pagination. The Node binding returns the rendered string and does not open a pager.
• paginateSymbols (boolean) — Prefer pager-compatible symbol rendering for terminal images.
• terminalInlineImages (boolean) — Render terminal images through a supported external viewer.
• terminalImageWidth (number) — Set inline terminal image width in character cells.

Line breaks, headings, and TOCs

• hardbreaks (boolean) — Treat soft line endings as hard line breaks.
• nobreaks (boolean) — Render soft breaks without inserting line breaks.
• generateHeaderIds (boolean) — Generate IDs for headings.
• headerAnchors (boolean) — Emit heading anchor elements instead of relying only on IDs.
• idFormat ("gfm" | "mmd") — Select GFM- or MultiMarkdown-style generated IDs.
• tocMin (number) — Set the minimum heading level included in generated TOCs.
• tocMax (number) — Set the maximum heading level included in generated TOCs.

Tables and lists

• relaxedTables (boolean) — Accept relaxed tables without a standard separator row.
• captionPosition ("above" | "below") — Place generated table captions above or below the table.
• perCellAlignment (boolean) — Enable alignment markers on individual table cells.
• allowMixedListMarkers (boolean) — Keep mixed bullet markers in one list where the mode permits.
• allowAlphaLists (boolean) — Enable alphabetic ordered-list markers.

Inline syntax and autolinks

• enableSupSub (boolean) — Enable superscript and subscript syntax.
• enableStrikethrough (boolean) — Enable ~~strikethrough~~.
• enableAutolink (boolean) — Automatically link recognized URLs and email addresses.
• obfuscateEmails (boolean) — Obfuscate email addresses in generated links.

Images

• embedImages (boolean) — Embed supported local images as base64 data URLs.
• enableImageCaptions (boolean) — Render eligible images as figures with captions.
• titleCaptionsOnly (boolean) — Require an image title instead of falling back to alt text for captions.

Citations and bibliographies

• enableCitations (boolean) — Parse citation syntax and process bibliography data. Unlike the Apex CLI, setting bibliography options here does not enable citations automatically.
• bibliographyFiles (string[]) — Load BibTeX, CSL JSON, or CSL YAML bibliography files. Pair with enableCitations: true.
• cslFile (string) — Apply a Citation Style Language file. Pair with enableCitations: true.
• suppressBibliography (boolean) — Process citations without appending a bibliography.
• linkCitations (boolean) — Link in-text citations to bibliography entries.
• showTooltips (boolean) — Add citation details as tooltips where supported.
• nocite (string) — Include uncited bibliography entries using a nocite expression.

See the citation guide for syntax and supported bibliography formats.

Indices

• enableIndices (boolean) — Parse index entries and generate an index.
• enableMmarkIndexSyntax (boolean) — Enable mmark index syntax.
• enableTextindexSyntax (boolean) — Enable TextIndex syntax.
• enableLeanpubIndexSyntax (boolean) — Enable Leanpub index syntax.
• suppressIndex (boolean) — Parse index entries without appending the generated index.
• groupIndexByLetter (boolean) — Group generated index entries by initial letter.

Wiki links

• wikilinkSpace ("dash" | "none" | "underscore" | "space") — Choose how spaces are written in wiki-link targets.
• wikilinkExtension (string) — Append an extension to generated wiki-link targets.
• wikilinkSanitize (boolean) — Sanitize generated wiki-link targets.

Styles, scripts, accessibility, and emoji

• scriptTags (string[]) — Add raw script-tag snippets to standalone output.
• embedStylesheet (boolean) — Embed stylesheet content instead of linking it.
• enableAria (boolean) — Add supported ARIA roles, labels, and relationships.
• enableEmojiAutocorrect (boolean) — Normalize supported emoji-related syntax and names.

Syntax highlighting

• codeHighlighter (string) — Select an external highlighter such as Pygments, Skylighting, or Shiki.
• codeLineNumbers (boolean) — Request line numbers from syntax highlighting.
• highlightLanguageOnly (boolean) — Highlight only code blocks that declare a language.
• codeHighlightTheme (string) — Select the external highlighter theme.

External highlighting may execute a highlighter installed on the system.

Integration-specific rendering

• enableWidont (boolean) — Prevent a lone final word where supported by moving it with a nonbreaking space.
• codeIsPoetry (boolean) — Apply poetry-oriented handling to code-like text.
• enableMarkdownInHtml (boolean) — Parse Markdown inside eligible HTML blocks.
• randomFootnoteIds (boolean) — Randomize generated footnote IDs to avoid collisions.
• enableHashtags (boolean) — Recognize hashtags.
• styleHashtags (boolean) — Add styling hooks to recognized hashtags.
• proofreaderMode (boolean) — Enable proofreader-oriented rendering behavior.
• hrPageBreak (boolean) — Treat horizontal rules as page breaks where supported.
• titleFromH1 (boolean) — Derive the document title from the first level-one heading.
• pageBreakBeforeFootnotes (boolean) — Insert a page break before the footnotes section.

AST filters

• astFilterCommands (string[]) — Run Pandoc-style JSON AST filter commands in order.
• astFilterStrict (boolean) — Fail conversion when an AST filter fails instead of continuing.

AST filters execute external commands. Do not enable filters supplied by untrusted input.

Supported platforms

Prebuilt native addons are published for:

• macOS arm64
• macOS x64
• Linux arm64
• Linux x64

The package requires Node.js 20 or newer. Windows and other platform/architecture combinations do not currently have prebuilt addons. No system cmark-gfm or libyaml installation is required on supported platforms; both libraries are statically linked.

If installation omits the optional platform package, loading Apex throws an error identifying the detected platform. Ensure optional dependencies are not disabled by your package-manager configuration.

Native and security considerations

convert() runs synchronously on the calling thread. For large documents or high-throughput servers, consider performing conversions in worker threads.

Some options intentionally access the filesystem or execute external programs: plugins, file includes, bibliography and CSL files, stylesheet and image embedding, syntax highlighters, and AST filters. Restrict these features when processing untrusted Markdown.

Local development

git clone --recurse-submodules https://github.com/ApexMarkdown/apex-node.git
cd apex-node
npm install
npm run build
npm test

If the repository was cloned without submodules:

git submodule update --init --recursive

To produce the prebuilt package for the current platform:

npm run package:prebuild

This writes prebuilds/@apexmarkdown/apex-<platform>-<arch>/.

More documentation

• Apex documentation
• Syntax
• Modes
• Command-line options
• Citations
• Tables
• Apex CLI and C library

License

MIT