MDEx is the fastest Markdown parser for Elixir, built on Rust for blazing performance. It transforms markdown into HTML, HEEx, JSON, XML, and more with native Phoenix LiveView integration.

How do I install MDEx?

Add {:mdex, "~> 0.11"} to your mix.exs dependencies, or run: mix igniter.install mdex

Does MDEx support Phoenix LiveView?

Yes, MDEx has native Phoenix LiveView support via the ~MD sigil which renders directly to Phoenix.LiveView.Rendered format, allowing you to use HEEx components inside markdown.

## See It In Action

Markdown in. Everything out.

# Markdown Input

[-][o][x]

# Welcome to **MDEx**

Features:
- Fast
- Extensible
- Phoenix-ready

```elixir
MDEx.to_html!("# Hello")
```

>> Output

<h1>Welcome to <strong>MDEx</strong></h1>
<p>Features:</p>
<ul>
  <li>Fast</li>
  <li>Extensible</li>
  <li>Phoenix-ready</li>
</ul>
<pre class="athl" style="...">
  <code class="language-elixir">
    <div class="line" data-line="1"><span style="...">
      MDEx.to_html!("# Hello")
    </span></div>
  </code>
</pre>

#MDEx.Document<17 nodes
├── 1 [heading] level: 1
│   ├── 2 [text] literal: "Welcome to "
│   └── 3 [strong]
│       └── 4 [text] literal: "MDEx"
├── 5 [paragraph]
│   └── 6 [text] literal: "Features:"
├── 7 [list] list_type: :bullet, tight: true
│   ├── 8 [list_item]
│   │   └── 9 [paragraph]
│   │       └── 10 [text] literal: "Fast"
│   ├── 11 [list_item]
│   │   └── 12 [paragraph]
│   │       └── 13 [text] literal: "Extensible"
│   └── 14 [list_item]
│       └── 15 [paragraph]
│           └── 16 [text] literal: "Phoenix-ready"
└── 17 [code_block] info: "elixir", fenced: true
>

%Phoenix.LiveView.Rendered{
  static: ["<h1>Welcome to <strong>MDEx</strong></h1>\n..."],
  dynamic: #Function<42.81571850/1 in :erl_eval.expr/6>,
  fingerprint: 52776307825337990075203022359966918684,
  root: false,
  caller: :not_available
}

{
  "type": "document",
  "children": [
    {
      "type": "heading",
      "level": 1,
      "children": [...]
    },
    {
      "type": "list",
      "list_type": "bullet",
      ...
    }
  ]
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document SYSTEM "CommonMark.dtd">
<document xmlns="http://commonmark.org/xml/1.0">
  <heading level="1">
    <text xml:space="preserve">Welcome to </text>
    <strong>
      <text xml:space="preserve">MDEx</text>
    </strong>
  </heading>
  <paragraph>
    <text xml:space="preserve">Features:</text>
  </paragraph>
  <list type="bullet" tight="true">
    <item><paragraph><text>Fast</text></paragraph></item>
    <item><paragraph><text>Extensible</text></paragraph></item>
    <item><paragraph><text>Phoenix-ready</text></paragraph></item>
  </list>
  <code_block info="elixir">MDEx.to_html!("# Hello")</code_block>
</document>

[
  %{"insert" => "Welcome to "},
  %{"attributes" => %{"bold" => true}, "insert" => "MDEx"},
  %{"attributes" => %{"header" => 1}, "insert" => "\n"},
  %{"insert" => "Features:\n"},
  %{"insert" => "Fast"},
  %{"attributes" => %{"list" => "bullet"}, "insert" => "\n"},
  %{"insert" => "Extensible"},
  %{"attributes" => %{"list" => "bullet"}, "insert" => "\n"},
  %{"insert" => "Phoenix-ready"},
  %{"attributes" => %{"list" => "bullet"}, "insert" => "\n"},
  ...
]

## Blazingly Fast

Light on memory. Heavy on throughput.

>> MDEx 0 ops/s

[x] fastest

Alternatives 0 ops/s 31x slower

average of Elixir markdown parsers

* Benchmarked on Apple M1 Pro [benchmark.exs]

┌─────────────────────────────────────┐

3,506x

less memory than alternatives

0.00184 MB vs 6.45 MB

└─────────────────────────────────────┘

## Features

+ + + +

{*} Phoenix HEEx Integration

docs →

Native rendering to Phoenix.LiveView.Rendered for LiveView integration.


              ~MD[# {@title}]HEEX

+ + + +

[#] Syntax Highlighting

docs →

100+ themes and 70+ languages powered by Tree-sitter and Neovim. Code blocks look beautiful out of the box.

>> autumnus.dev

+ + + +

</> Document Manipulation

docs →

Full AST with Enumerable, Collectable, and Access protocols. Parse, traverse, and transform.


              MDEx.Document

+ + + +

[+] Plugin System

docs →

Extend functionality with custom plugins. Process documents at any stage of the pipeline.


              GFM, Mermaid, KaTeX

+ + + +

>>> AI Streaming Support

docs →

Process incomplete markdown fragments progressively. Perfect for ChatGPT-style interfaces.


              streaming: true

+ + + +

<-> Multiple Output Formats

docs →

Output to HTML, HEEx, JSON, XML, Quill Delta, and Markdown. One parser, many outputs.


              to_{html,json,xml,delta,markdown}

+ + + +

[!] Safety & Sanitization

docs →

Built-in XSS protection with configurable sanitization. Safely render untrusted markdown content.


              MDEx.Document.default_sanitize_options()

+ + + +

``` Code Block Decorators

docs →

Override themes, highlight lines, and add CSS classes to code blocks with inline attributes.


              ```js theme=nord highlight_lines="2-3"

+ + + +

:) Emoji Built-in

docs →

Shortcode support for emoji conversion. Write :rocket: and get the actual 🚀 emoji.


              shortcodes: true

## Phoenix LiveView Ready

Write markdown with HEEx components. Render directly to LiveView.

// page_live.ex [-][o][x]

def render(assigns) do
  ~MD"""
  # Welcome, {@user.name}!

  <.button phx-click="upgrade">
    Upgrade to Pro
  </.button>

  Your plan: **{@plan}**
  """HEEX
end

>> Rendered Output

Welcome, John!

Q: Can MDEx handle AI streaming applications?

Yes, MDEx supports streaming mode for processing incomplete markdown fragments progressively, perfect for ChatGPT-style interfaces. Enable it with MDEx.new(streaming: true).

Your plan: Free

## Built for AI Applications

Stream incomplete markdown fragments as they arrive. Perfect for ChatGPT-style interfaces.

[*] AI Assistant [-][o][x]

>> Write a poem about Elixir

_

// How it works

MDEx.new(streaming: true)
|> MDEx.Document.put_markdown("**The Rust")
|> MDEx.to_html!()
# => "<p><strong>The Rust</strong></p>"

## Why MDEx?

Feature	MDEx	Earmark	md	cmark
Active	[x]	[x]	[x]	[ ]
Pure Elixir	[ ]	[x]	[x]	[ ]
Extensible	[x]	[x]	[x]	[ ]
Syntax Highlighting	[x]	[ ]	[ ]	[ ]
Code Block Decorators	[x]	[ ]	[ ]	[ ]
Streaming (fragments)	[x]	[ ]	[ ]	[ ]
Phoenix HEEx components	[x]	[ ]	[ ]	[ ]
AST	[x]	[x]	[x]	[ ]
AST to Markdown	[x]	[~]²	[ ]	[ ]
To HTML	[x]	[x]	[x]	[x]
To JSON	[x]	[ ]	[ ]	[ ]
To XML	[x]	[ ]	[ ]	[x]
To Manpage	[ ]	[ ]	[ ]	[x]
To LaTeX	[ ]	[ ]	[ ]	[x]
To Quill Delta	[x]	[ ]	[ ]	[ ]
Emoji	[x]	[ ]	[ ]	[ ]
GFM³	[x]	[x]	[ ]	[ ]
GLFM⁴	[x]	[ ]	[ ]	[ ]
Discord⁵	[~]¹	[ ]	[ ]	[ ]

¹ Partial support

² Possible with earmark_reversal

³ GitHub Flavored Markdown

⁴ GitLab Flavored Markdown

⁵ Discord Flavored Markdown

> What People Say

# Ready?

Get started with MDEx in under a minute.


              $ mix igniter.install mdex

[ Read the Docs ] View on GitHub Hex.pm

# _

## Getting Started

## See It In Action

## Blazingly Fast

## Features

{*} Phoenix HEEx Integration

[#] Syntax Highlighting

</> Document Manipulation

[+] Plugin System

>>> AI Streaming Support

<-> Multiple Output Formats

[!] Safety & Sanitization

``` Code Block Decorators

:) Emoji Built-in

## Phoenix LiveView Ready

Welcome, John!

## Built for AI Applications

## Why MDEx?

> What People Say

# Ready?