README

A lightweight, dependency-free PHP library for converting Markdown into Slack-compatible mrkdwn. It preserves code blocks, handles tables, blockquotes, lists, and more for seamless Slack messaging.

💡 What is this?

An easy-to-use, dependency-free PHP 7.4+ library that converts Markdown—headings, text formatting, lists, tables, blockquotes, and code blocks—into Slack’s mrkdwn format. Ideal for bots, integrations, or any app sending rich text to Slack.

✨ Features

- Headings (H1–H6 → `*Heading*`)
- Text formatting:
  - Bold (`**bold**` → `*bold*`)
  - Italic (`*italic*` or `_italic_` → `_italic_`)
  - Strikethrough (`~~strike~~` → `~strike~`)
- Lists:
  - Unordered & ordered (with nesting)
  - Task lists (`- [ ]` / `- [x]` → `• ☐` / `• ☑`)
- Tables (simple text tables with bold headers)
- Links & images:
  - `[text](url)` → `<url|text>`
  - `![alt](url)` → `<url>`
- Code:
  - Inline `` `code` ``
  - Fenced code blocks (```…```), preserving language hint
- Blockquotes (`> quote`)
- Horizontal rules (`---`, `***`, `___` → `──────────`)

📋 Supported Conversions

Markdown	Slack mrkdwn
`# Heading`	`Heading`
`Bold`	`Bold`
`Italic` / `_Italic_`	`_Italic_`
`~~Strike~~`	`~Strike~`
`- [ ] Task`	`• ☐ Task`
`- [x] Task`	`• ☑ Task`
`- Item` / `1. Item`	`• Item` / `1. Item`
`Inline code`	`Inline code`
```lang	```lang
code	code
```	```
`> Quote`	`> Quote`
`---` / `***` / `___`	`──────────`

🔌 Plugin System

You can extend the converter with custom plugins (global, line or block scope):

use DaryleDeSilva\MarkdownToMrkdwn\Converter;

$converter = new Converter();

// Global plugin (runs on full text)
$converter->registerPlugin(
    'addQuotes',
    fn(string $text) => "\"{$text}\"",
    priority: 10,
    scope: 'global'
);

// Line plugin (before standard conversion)
$converter->registerPlugin(
    'linePrefix',
    fn(string $line) => "[LINE] {$line}",
    priority: 20,
    scope: 'line',
    timing: 'before'
);

echo $converter->convert("**Hello**, world!");

Advanced plugin examples

// Function plugin: convert entire text to uppercase
$converter->registerPlugin(
    name: 'toUpper',
    converter_func: fn(string $text) => strtoupper($text),
    priority: 10,
    scope: 'line',
    timing: 'after'
);

// Regex plugin: mask email addresses
$converter->registerRegexPlugin(
    name: 'maskEmails',
    pattern: '/[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\\.[a-zA-Z0-9-.]+/',
    replacement: '[EMAIL]',
    priority: 20,
    timing: 'after'
);

Error handling

If an error occurs during conversion, the original Markdown text is returned unmodified.

🛠 Requirements

PHP 7.4 or higher

📦 Installation

composer require daryledesilva/markdown-to-mrkdwn-php

🚀 Usage

use DaryleDeSilva\MarkdownToMrkdwn\Converter;

$converter = new Converter();
echo $converter->convert("**Hello**, [Slack](https://slack.com)!");

🧪 Testing

composer install
composer test

🔗 Testing in Slack

You can preview the converted mrkdwn in Slack’s Block Kit Builder:
https://app.slack.com/block-kit-builder/

📄 License

MIT

Inspired by the original Python package markdown_to_mrkdwn.

Created by @daryledesilva

daryledesilva / markdown-to-mrkdwn-php

Maintainers

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