markdown-it vs showdown vs remarkable
Markdown Parsing Libraries for JavaScript Applications
Search packages..
markdown-itshowdownremarkableSimilar Packages:

Markdown Parsing Libraries for JavaScript Applications

markdown-it, remarkable, and showdown are JavaScript libraries that convert Markdown syntax into HTML. They enable developers to render user-authored or content-driven Markdown in web applications, supporting features like extensibility, security, and customization. Each library offers a different balance of performance, configurability, and ease of use, making them suitable for distinct project requirements.

Npm Package Weekly Downloads Trend

3 Years

Github Stars Ranking

Stat Detail

Package
Downloads
Stars
Size
Issues
Publish
License
markdown-it19,129,85721,116768 kB5824 days agoMIT
showdown1,440,93814,836801 kB233-MIT
remarkable1,193,7055,824-1326 years agoMIT

Markdown Parsing in JavaScript: markdown-it vs remarkable vs showdown

When you need to turn Markdown into HTML in a JavaScript app — whether for a blog editor, a documentation site, or user comments — picking the right parser matters. markdown-it, remarkable, and showdown all solve this problem, but they do it in very different ways. Let’s compare how they handle real-world needs like security, extensibility, and performance.

⚙️ Core Architecture: Rules, Tokens, and Extensions

markdown-it uses a modular pipeline based on tokens and rules. It parses Markdown into a token stream, then renders those tokens to HTML using configurable renderer functions. This design makes it easy to inspect, modify, or extend behavior at any stage.

// markdown-it: add a custom rule
const md = require('markdown-it')();
md.core.ruler.push('my_rule', function(state) {
  // manipulate state.tokens here
});

remarkable also uses a token-based approach but with a less granular API. It exposes a few hooks (core, block, inline) but doesn’t allow deep manipulation of the token stream like markdown-it. Its architecture prioritizes speed over flexibility.

// remarkable: define a custom inline rule
const Remarkable = require('remarkable');
const md = new Remarkable();
md.inline.ruler.push('my_rule', function(state, silent) {
  // limited access to parsing state
});

showdown uses a regex-and-replace engine with an extension system based on preprocessors, postprocessors, listeners, and type-specific handlers. It’s less structured than token-based parsers but easier to grasp for simple overrides.

// showdown: create an extension
const showdown = require('showdown');
const converter = new showdown.Converter({
  extensions: [{
    type: 'output',
    filter: function(text) {
      return text.replace(/CUSTOM/g, '<b>custom</b>');
    }
  }]
});

🔒 Security: Preventing XSS by Default

All three libraries do not sanitize HTML by default. If your Markdown includes raw HTML (e.g., <script> tags), it will be rendered as-is — a major XSS risk.

markdown-it encourages safe usage via the html: false option (default) and recommends pairing with a sanitizer like DOMPurify:

const md = require('markdown-it')({ html: false }); // blocks HTML tags
// For trusted HTML + sanitization:
const dirty = md.render('<img src=x onerror=alert(1)>');
const clean = DOMPurify.sanitize(dirty);

remarkable behaves similarly — html: false is default, but you must handle sanitization yourself if enabling HTML.

const md = new Remarkable({ html: false }); // strips HTML

showdown defaults to noHtml: false, meaning HTML is allowed unless explicitly disabled — a potential footgun:

// Dangerous: allows raw HTML by default
const converter = new showdown.Converter();

// Safe: disable HTML
const safeConverter = new showdown.Converter({ noHtml: true });

💡 Always disable raw HTML or sanitize output when rendering untrusted Markdown.

🧩 Extensibility: Adding Custom Syntax

Need to support GitHub-style task lists, LaTeX math, or custom shortcodes? Extensibility becomes critical.

markdown-it shines here with hundreds of official and community plugins (e.g., markdown-it-task-lists, markdown-it-katex). Plugins can hook into parsing, rendering, or both.

const md = require('markdown-it')()
  .use(require('markdown-it-task-lists'));

console.log(md.render('- [x] done')); // renders checkbox

remarkable has minimal plugin support. You can write custom rules, but there’s no ecosystem of reusable extensions. The project hasn’t seen significant updates since 2018.

// No official plugins; you build everything from scratch

showdown supports extensions, but they’re less powerful than markdown-it’s plugin system. Extensions can’t easily modify parsing logic — they mostly transform text before or after conversion.

// showdown extension for :emoji:
const emojiExt = {
  type: 'lang',
  regex: /:([a-z]+):/g,
  replace: '<span class="emoji">$1</span>'
};
const converter = new showdown.Converter({ extensions: [emojiExt] });

🖥️ Browser and Server Support

All three work in Node.js and browsers, but with caveats.

markdown-it is designed for both environments. The core is lightweight, and plugins can be loaded conditionally.

remarkable works in browsers but hasn’t been optimized for modern bundlers. Its last release was years ago.

showdown explicitly supports browsers and even provides a global Showdown.converter. It’s commonly used in client-side editors.

<!-- showdown in browser -->
<script src="showdown.min.js"></script>
<script>
  const converter = new showdown.Converter();
  document.getElementById('preview').innerHTML = 
    converter.makeHtml('# Hello');
</script>

📏 Standards Compliance and Edge Cases

markdown-it follows CommonMark closely and passes most of its test suite. It handles edge cases like nested lists, emphasis ambiguity, and code fences reliably.

remarkable also aims for CommonMark compliance but lags behind in updates. Some newer Markdown constructs may not parse correctly.

showdown does not fully comply with CommonMark. It follows its own interpretation, closer to “classic” Markdown or GitHub Flavored Markdown (GFM) depending on options.

// Example: GFM table support
const input = "| a | b |\n|---|---|\n| 1 | 2 |";

// markdown-it: requires markdown-it-tables plugin
// remarkable: built-in support
// showdown: enable 'tables' option
const converter = new showdown.Converter({ tables: true });

🛑 Maintenance Status

  • markdown-it: Actively maintained, frequent releases, large community.
  • remarkable: No longer under active development (per its GitHub README). Last npm release was in 2018. Not recommended for new projects.
  • showdown: Actively maintained, regular updates, stable API.

🆚 Summary: Key Differences

Featuremarkdown-itremarkableshowdown
ArchitectureToken-based, modularToken-based, minimal hooksRegex-based, extension hooks
ExtensibilityRich plugin ecosystemLimited, no pluginsBasic extensions
Security Defaultshtml: false (safe)html: false (safe)noHtml: false (unsafe!)
StandardsCommonMark compliantPartially compliantNon-compliant (GFM-like)
Maintenance✅ Active❌ Deprecated✅ Active
Best ForComplex apps, custom syntaxLegacy projects (avoid new)Simple converters, client-side

💡 Final Recommendation

  • For new projects requiring flexibility, security, and future-proofing: go with markdown-it. Its plugin system and active maintenance make it the most robust choice.
  • For simple, client-side Markdown previews with minimal setup: showdown is reliable and easy to drop in.
  • Avoid remarkable in new codebases — its lack of updates and plugin support makes it a liability long-term.

Remember: no matter which library you choose, always sanitize output when rendering untrusted Markdown to prevent XSS attacks.

How to Choose: markdown-it vs showdown vs remarkable

  • markdown-it:

    Choose markdown-it if you need a highly extensible, standards-compliant Markdown parser with a rich plugin ecosystem. It supports CommonMark and provides fine-grained control over parsing and rendering through rules and plugins. Ideal for applications requiring custom syntax extensions (e.g., math, footnotes) or strict security via HTML sanitization.

  • showdown:

    Choose showdown if you need a battle-tested, flexible converter with a simple API and good browser support. It includes options for flavor customization (GitHub, vanilla), client-side usage, and extension hooks. While not as fast or modular as markdown-it, it remains actively maintained and suitable for straightforward Markdown-to-HTML conversion in both frontend and backend contexts.

  • remarkable:

    Choose remarkable if you prioritize speed and a clean, minimal API without needing extensive plugin support. It offers solid CommonMark compliance and built-in syntax highlighting but lacks active maintenance—official documentation notes it is no longer under active development. Avoid for new projects unless legacy compatibility is required.

Similar Npm Packages to markdown-it

markdown-it is a powerful Markdown parser and compiler for JavaScript. It allows developers to convert Markdown text into HTML, making it a popular choice for applications that require rich text formatting. With its extensible architecture, markdown-it supports a variety of plugins that can enhance its functionality, such as adding support for tables, footnotes, and custom syntax. Its performance and flexibility make it suitable for both small projects and large applications that need to render Markdown content efficiently.

While markdown-it is a robust option, there are other libraries available that also provide Markdown parsing capabilities. Here are a few alternatives:

  • remark is a Markdown processor powered by plugins. It is part of the unified ecosystem, which allows for a wide range of transformations on Markdown content. remark focuses on the syntax tree, enabling developers to manipulate Markdown in a more programmatic way. This makes it an excellent choice for projects that require extensive customization and processing of Markdown content, such as static site generators or documentation tools. With its plugin architecture, remark can be tailored to fit specific needs, making it highly versatile.

  • showdown is another popular Markdown to HTML converter. It is lightweight and easy to use, making it a great choice for simple applications that need to convert Markdown to HTML without the overhead of additional features. showdown is particularly useful for projects where performance is a priority, as it has a minimal footprint and straightforward API. If you need a quick and efficient way to render Markdown in your application without the need for extensive customization, showdown is an excellent option.

To compare these packages, check out the following link: Comparing markdown-it vs remark vs showdown.

Similar Npm Packages to showdown

showdown is a popular JavaScript library that converts Markdown into HTML. It is lightweight and easy to use, making it a great choice for developers looking to integrate Markdown support into their web applications. Showdown provides a simple API for converting Markdown text to HTML, and it supports a variety of Markdown features, including tables, lists, and code blocks. Its flexibility and ease of integration make it a preferred option for many developers working with Markdown content.

However, there are several alternatives to Showdown that also provide Markdown parsing and rendering capabilities. Here are a few noteworthy options:

  • markdown-it is a powerful Markdown parser that is highly extensible and customizable. It supports a wide range of Markdown features and allows developers to create plugins to extend its functionality. Markdown-it is known for its performance and flexibility, making it suitable for applications that require advanced Markdown processing. If you need a robust solution with a rich plugin ecosystem, markdown-it is an excellent choice.

  • marked is another fast and lightweight Markdown parser that is designed for speed and efficiency. It is simple to use and provides a straightforward API for converting Markdown to HTML. Marked is particularly known for its performance, making it ideal for applications that need to render large amounts of Markdown content quickly. If you prioritize speed and simplicity, marked is a solid option.

  • remarkable is a Markdown parser that focuses on extensibility and customization. It offers a variety of features, including support for custom syntax and plugins. Remarkable is designed to be fast and efficient while providing a high level of customization for developers who need specific Markdown features. If you are looking for a parser that allows for deep customization, remarkable is worth considering.

To compare these packages and see how they stack up against each other, check out the following link: Comparing markdown-it vs marked vs remarkable vs showdown.

Similar Npm Packages to remarkable

remarkable is a fast and flexible Markdown parser and compiler for JavaScript. It allows developers to convert Markdown text into HTML with a focus on performance and extensibility. With its simple API and support for custom rules, remarkable is a great choice for projects that require Markdown processing. However, there are several alternatives in the Markdown parsing ecosystem that also offer unique features. Here are a few notable ones:

  • markdown-it is a powerful Markdown parser that emphasizes extensibility and performance. It supports a wide range of plugins and features, allowing developers to customize the parsing process to fit their needs. With its strong focus on compliance with the CommonMark specification, markdown-it is ideal for projects that require strict adherence to Markdown standards. Its flexibility and plugin ecosystem make it suitable for both simple and complex Markdown processing tasks.
  • showdown is another popular Markdown to HTML converter that is lightweight and easy to use. It provides a straightforward API for converting Markdown text into HTML and is particularly well-suited for browser-based applications. showdown is a great choice for developers looking for a simple and effective way to integrate Markdown parsing into their web applications without the need for extensive configuration or setup.

To explore how remarkable compares with markdown-it and showdown, check out the comparison: Comparing markdown-it vs remarkable vs showdown.

README for markdown-it

markdown-it

CI NPM version Coverage Status Gitter

Markdown parser done right. Fast and easy to extend.

Live demo

  • Follows the CommonMark spec + adds syntax extensions & sugar (URL autolinking, typographer).
  • Configurable syntax! You can add new rules and even replace existing ones.
  • High speed.
  • Safe by default.
  • Community-written plugins and other packages on npm.

Table of content

Install

node.js:

npm install markdown-it

browser (CDN):

Usage examples

See also:

Simple

// node.js
// can use `require('markdown-it')` for CJS
import markdownit from 'markdown-it'
const md = markdownit()
const result = md.render('# markdown-it rulezz!');

// browser with UMD build, added to "window" on script load
// Note, there is no dash in "markdownit".
const md = window.markdownit();
const result = md.render('# markdown-it rulezz!');

Single line rendering, without paragraph wrap:

import markdownit from 'markdown-it'
const md = markdownit()
const result = md.renderInline('__markdown-it__ rulezz!');

Init with presets and options

(*) presets define combinations of active rules and options. Can be "commonmark", "zero" or "default" (if skipped). See API docs for more details.

import markdownit from 'markdown-it'

// commonmark mode
const md = markdownit('commonmark')

// default mode
const md = markdownit()

// enable everything
const md = markdownit({
  html: true,
  linkify: true,
  typographer: true
})

// full options list (defaults)
const md = markdownit({
  // Enable HTML tags in source
  html:         false,

  // Use '/' to close single tags (<br />).
  // This is only for full CommonMark compatibility.
  xhtmlOut:     false,

  // Convert '\n' in paragraphs into <br>
  breaks:       false,

  // CSS language prefix for fenced blocks. Can be
  // useful for external highlighters.
  langPrefix:   'language-',

  // Autoconvert URL-like text to links
  linkify:      false,

  // Enable some language-neutral replacement + quotes beautification
  // For the full list of replacements, see https://github.com/markdown-it/markdown-it/blob/master/lib/rules_core/replacements.mjs
  typographer:  false,

  // Double + single quotes replacement pairs, when typographer enabled,
  // and smartquotes on. Could be either a String or an Array.
  //
  // For example, you can use '«»„“' for Russian, '„“‚‘' for German,
  // and ['«\xA0', '\xA0»', '‹\xA0', '\xA0›'] for French (including nbsp).
  quotes: '“”‘’',

  // Highlighter function. Should return escaped HTML,
  // or '' if the source string is not changed and should be escaped externally.
  // If result starts with <pre... internal wrapper is skipped.
  highlight: function (/*str, lang*/) { return ''; }
});

Plugins load

import markdownit from 'markdown-it'

const md = markdownit
  .use(plugin1)
  .use(plugin2, opts, ...)
  .use(plugin3);

Syntax highlighting

Apply syntax highlighting to fenced code blocks with the highlight option:

import markdownit from 'markdown-it'
import hljs from 'highlight.js' // https://highlightjs.org

// Actual default values
const md = markdownit({
  highlight: function (str, lang) {
    if (lang && hljs.getLanguage(lang)) {
      try {
        return hljs.highlight(str, { language: lang }).value;
      } catch (__) {}
    }

    return ''; // use external default escaping
  }
});

Or with full wrapper override (if you need assign class to <pre> or <code>):

import markdownit from 'markdown-it'
import hljs from 'highlight.js' // https://highlightjs.org

// Actual default values
const md = markdownit({
  highlight: function (str, lang) {
    if (lang && hljs.getLanguage(lang)) {
      try {
        return '<pre><code class="hljs">' +
               hljs.highlight(str, { language: lang, ignoreIllegals: true }).value +
               '</code></pre>';
      } catch (__) {}
    }

    return '<pre><code class="hljs">' + md.utils.escapeHtml(str) + '</code></pre>';
  }
});

Linkify

linkify: true uses linkify-it. To configure linkify-it, access the linkify instance through md.linkify:

md.linkify.set({ fuzzyEmail: false });  // disables converting email to link

API

API documentation

If you are going to write plugins, please take a look at Development info.

Syntax extensions

Embedded (enabled by default):

Via plugins:

Manage rules

By default all rules are enabled, but can be restricted by options. On plugin load all its rules are enabled automatically.

import markdownit from 'markdown-it'

// Activate/deactivate rules, with currying
const md = markdownit()
  .disable(['link', 'image'])
  .enable(['link'])
  .enable('image');

// Enable everything
const md = markdownit({
  html: true,
  linkify: true,
  typographer: true,
});

You can find all rules in sources:

Benchmark

Here is the result of readme parse at MB Pro Retina 2013 (2.4 GHz):

npm run benchmark-deps
benchmark/benchmark.mjs readme

Selected samples: (1 of 28)
 > README

Sample: README.md (7774 bytes)
 > commonmark-reference x 1,222 ops/sec ±0.96% (97 runs sampled)
 > current x 743 ops/sec ±0.84% (97 runs sampled)
 > current-commonmark x 1,568 ops/sec ±0.84% (98 runs sampled)
 > marked x 1,587 ops/sec ±4.31% (93 runs sampled)

Note. CommonMark version runs with simplified link normalizers for more "honest" compare. Difference is ≈1.5×.

As you can see, markdown-it doesn't pay with speed for its flexibility. Slowdown of "full" version caused by additional features not available in other implementations.

markdown-it for enterprise

Available as part of the Tidelift Subscription.

The maintainers of markdown-it and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use. Learn more.

Authors

markdown-it is the result of the decision of the authors who contributed to 99% of the Remarkable code to move to a project with the same authorship but new leadership (Vitaly and Alex). It's not a fork.

References / Thanks

Big thanks to John MacFarlane for his work on the CommonMark spec and reference implementations. His work saved us a lot of time during this project's development.

Related Links:

Ports

npm-compare.com is an independent website designed to help developers choose the most suitable npm packages. We are not affiliated with npm, Inc, the official website for the npm registry. Note that npm is a registered trademark of npm, Inc. Please share your feedback via our GitHub repository. For more details, please refer to our Terms & Privacy.