MDEx is an Elixir Markdown library powered by a Rust parser. It transforms markdown into HTML, HEEx, JSON, XML, and more with native Phoenix LiveView integration.

How do I install MDEx?

Add MDEx 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
Enum.map(1..3, &(&1 * 2))
```

>> Output

#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
>

<h1>Welcome to <strong>MDEx</strong></h1>
<p>Features:</p>
<ul>
  <li>Fast</li>
  <li>Extensible</li>
  <li>Phoenix-ready</li>
</ul>
<pre class="lumis" style="...">
  <code class="language-elixir">
    <div class="l-line" data-line="1"><span style="...">
      Enum.map(1..3, &(&1 * 2))
    </span></div>
  </code>
</pre>

%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">Enum.map(1..3, &(&1 * 2))</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"},
  ...
]

*Welcome to MDEx*
Features:
- Fast
- Extensible
- Phoenix-ready
```
Enum.map(1..3, &(&1 * 2))
```

## Blazingly Fast

Light on memory. Heavy on throughput.

mdex_native 0 ops/s

Rust NIF · direct comrak bindings · 0.00008 MB

>> MDEx 0 ops/s

full MDEx document pipeline · 2.36 MB

MDEx benchmark [benchmark.exs]

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

0 ms

with the ~MD sigil

rendered at compile time

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

## Features

+ + + +

{*} Phoenix HEEx Integration

docs →

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


              ~MD[# {@title}]HEEX

+ + + +

[#] Syntax Highlighting

docs →

Choose 110+ Tree-sitter languages and 250+ Neovim themes with Lumis, or use Syntect with Sublime Text grammars.

>> Lumis >> Syntect

+ + + +

</> 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.

>> Plugins

+ + + +

>>> 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, Markdown, and Slack mrkdwn. One parser, many outputs.


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

+ + + +

[!] Safe by Default

docs →

Raw HTML is omitted by default. Opt into escaping, sanitization, or unsafe rendering when your content requires it.

>> Safety

+ + + +

``` 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 token fragments as they arrive. Made for AI-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?

MDEx feature comparison with other Elixir and Erlang Markdown libraries
Feature	MDEx	mdex_native	Earmark	md	cmark	erlang-markdown
Active	[x]	[x]	[~]⁵	[x]	[ ]	[x]
Pure Elixir	[~]⁶	[ ]	[x]	[x]	[ ]	[x]
Extensible	[x]	[ ]	[x]	[x]	[ ]	[~]⁹
Syntax Highlighting	[x]	[x]	[ ]	[ ]	[ ]	[ ]
Code Block Decorators	[x]	[ ]	[ ]	[ ]	[ ]	[ ]
Streaming (fragments)	[x]	[ ]	[ ]	[ ]	[ ]	[ ]
Phoenix HEEx components	[x]	[ ]	[ ]	[ ]	[ ]	[ ]
MDX (JS)	[ ]	[ ]	[ ]	[ ]	[ ]	[x]
Kramdown attributes	[ ]	[ ]	[~]⁸	[ ]	[ ]	[ ]
EEx support	[x]	[ ]	[x]	[ ]	[ ]	[ ]
Custom syntax DSL	[ ]	[ ]	[ ]	[x]	[ ]	[ ]
AST	[x]	[x]	[x]	[x]	[ ]	[x]
AST to Markdown	[x]	[x]	[~]⁷	[ ]	[ ]	[ ]
To HTML	[x]	[x]	[x]	[x]	[x]	[x]
To JSON	[x]	[ ]	[ ]	[ ]	[ ]	[ ]
To XML	[x]	[x]	[ ]	[ ]	[x]	[ ]
To Manpage	[ ]	[ ]	[ ]	[ ]	[x]	[ ]
To LaTeX	[ ]	[ ]	[ ]	[ ]	[x]	[ ]
To Quill Delta	[x]	[ ]	[ ]	[ ]	[ ]	[ ]
To Slack	[x]	[ ]	[ ]	[ ]	[ ]	[ ]
Emoji	[x]	[x]	[ ]	[ ]	[ ]	[ ]
GFM²	[x]	[x]	[x]	[ ]	[ ]	[x]
GLFM³	[x]	[x]	[ ]	[ ]	[ ]	[ ]
Discord⁴	[~]¹	[~]¹	[ ]	[ ]	[ ]	[ ]

¹ Partial support

² GitHub Flavored Markdown

³ GitLab Flavored Markdown

⁴ Discord Flavored Markdown

⁵ Earmark is currently marked as retired

⁶ MDEx depends on mdex_native, which uses Rustler

⁷ Possible with earmark_reversal

⁸ EarmarkParser supports Kramdown-style attributes

⁹ No custom plugin API

> 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

[!] Safe by Default

``` Code Block Decorators

:) Emoji Built-in

## Phoenix LiveView Ready

Welcome, John!

## Built for AI Applications

## Why MDEx?

> What People Say

# Ready?