html_to_markdown

High-performance HTML to Markdown converter for Dart and Flutter, powered by the Rust html-to-markdown engine via FFI bindings. 150-280 MB/s throughput — 10-80x faster than pure Dart alternatives.

Features

• Blazing fast: Rust-powered conversion engine via FFI
• Byte-identical output: Matches the Rust core exactly for all input
• Full metadata extraction: Title, description, author, keywords, OpenGraph, JSON-LD
• Comprehensive options: 40+ conversion settings (heading style, code blocks, links, whitespace, etc.)
• Visitor pattern: Customize element-level conversion behavior
• Cross-platform: Android, iOS, macOS, Linux, Windows

Installation

dart pub add html_to_markdown

Quick Start

import 'package:html_to_markdown/html_to_markdown.dart';

void main() {
  final html = '<h1>Hello World</h1><p>This is a <strong>test</strong>.</p>';

  // Basic conversion
  final result = convert(html);
  print(result.content);
  // # Hello World
  //
  // This is a **test**.
}

Configuration

final options = ConversionOptions()
  ..headingStyle = HeadingStyle.setext
  ..linkStyle = LinkStyle.referenced
  ..extractMetadata = true
  ..wrap = true
  ..wrapWidth = 80;

final result = convert(html, options: options);

Metadata Extraction

final options = ConversionOptions()..extractMetadata = true;
final result = convert(htmlWithMeta, options: options);

print(result.metadata?.title);       // Page title
print(result.metadata?.description); // Meta description
print(result.metadata?.author);      // Author
print(result.metadata?.keywords);    // Keywords list

Custom Visitor

class ScriptStripper extends Visitor {
  @override
  VisitResult visitElementStart(NodeContext ctx) {
    if (ctx.tagName == 'script' || ctx.tagName == 'style') {
      return VisitResult.skip;
    }
    return VisitResult.continue_;
  }
}

final result = convert(html, visitor: ScriptStripper());

Platform Support

Platform	Arch	Status
macOS	arm64, x64	✓
Linux	arm64, x64	✓
Windows	x64	✓
Android	arm64-v8a, armeabi-v7a, x86_64	✓
iOS	arm64	✓
Web	—	Not supported (use WASM binding)

API Reference

Functions

• convert(String html, {ConversionOptions? options, Visitor? visitor}) → ConversionResult

Classes

• ConversionOptions — 40+ configuration fields
• ConversionResult — Output with content, metadata, tables, images, warnings
• HtmlMetadata — Extracted page metadata
• Visitor — Abstract class with 38 element-level callbacks
• NodeContext — Context passed to visitor callbacks

Enums

HeadingStyle, LinkStyle, CodeBlockStyle, WhitespaceMode, OutputFormat, NewlineStyle, HighlightStyle, ListIndentType, PreprocessingPreset, VisitResult, NodeType, WarningKind

Exceptions

HtmlToMarkdownException, InvalidInputException, ConversionErrorException

Development

The native library (libhtml_to_markdown_ffi) must be built before running tests:

# Build the Rust FFI library
cargo build --release -p html-to-markdown-ffi

# Run tests
cd packages/dart
dart pub get
dart test

Related

• Rust core
• kreuzberg — Document intelligence framework
• All language bindings