mdparser

Native C CommonMark + GitHub Flavored Markdown parser for PHP. ~10-20× faster than pure-PHP alternatives (Parsedown, cebe, michelf) on a clean optimized build, targeting CommonMark 0.31 (652/652 spec examples pass; see docs/spec-coverage.md). GFM extensions: tables, strikethrough, task lists, autolinks, tagfilter. Installable via PIE (the PHP Foundation's PECL successor); ships as a single .so. PHP 8.2 minimum, OO API with final classes and readonly options.

# PIE (PHP Foundation's extension installer; uses the composer.json
# at the repo root with type: "php-ext")
pie install iliaal/mdparser

On a minimal PHP image (e.g. php:8.x-cli from Docker Hub), PIE needs a few build tools installed first:

# Debian/Ubuntu
sudo apt install -y git bison libtool-bin

# macOS
brew install bison libtool

git clone https://github.com/iliaal/mdparser.git
cd mdparser
phpize && ./configure --enable-mdparser
make -j
sudo make install
echo 'extension=mdparser.so' | sudo tee /etc/php/conf.d/mdparser.ini

Pre-built DLLs for PHP 8.2, 8.3, 8.4, and 8.5 (TS/NTS, x86/x64) are attached to each GitHub release.

use MdParser\Parser;
use MdParser\Options;

// Default parser: safe mode on, GFM extensions on.
$parser = new Parser();
echo $parser->toHtml('# Hello');
// <h1>Hello</h1>

// Custom options via named arguments. All fields readonly.
$parser = new Parser(new Options(
    smart: true,          // --- -> em dash, -- -> en dash, "..." -> curly
    footnotes: true,      // enable [^ref] / [^ref]: syntax
    unsafe: false,        // raw HTML is escaped (default)
));
echo $parser->toHtml($markdown);

// Presets for common setups.
$github     = new Parser(Options::github());     // GFM + footnotes + alerts
$strict     = new Parser(Options::strict());     // CommonMark, no bare-URL autolinks
$permissive = new Parser(Options::permissive()); // trusted input: raw HTML passes through

// Three output formats from one parser.
$html = $parser->toHtml($markdown);
$xml  = $parser->toXml($markdown);   // CommonMark XML, DOCTYPE-wrapped
$ast  = $parser->toAst($markdown);   // nested arrays, see below

// AST shape is documented in tests/006_ast.phpt. Brief example:
// [
//   'type' => 'document',
//   'children' => [
//     ['type' => 'heading', 'level' => 1, 'children' => [
//        ['type' => 'text', 'literal' => 'Hello'],
//     ]],
//   ],
// ]

Against the major pure-PHP Markdown libraries, on PHP 8.4 (clean optimized build, each parser in its default configuration):

Against the slowest pure-PHP parser the gap reaches ~45×. bench/README.md has the methodology, all parsers, caveats, league/commonmark notes, and reproduction steps. Benchmark a clean optimized PHP build; a debug or ASan build skews the numbers.

Comparison with the major pure-PHP Markdown libraries. "via ext" means the feature exists but requires opting in to a non-default extension; "Extra" means the feature ships in the library's Markdown Extra dialect, not its base mode; "✗" means the feature is not supported at all.

md4c also ships dialect extensions beyond CommonMark + GFM. Each one is an opt-in Options flag, off by default: latexMath ($inline$, $$block$$), wikiLinks ([[target]]), spoilers (||text||), underline, highlight (==text==), superscript (^text^), subscript (~text~), admonitions (GitHub-style > [!NOTE] alert blocks), insert (++text++ renders <ins>), and preserveBlankLines (blank-line runs are reported instead of discarded, visible in toXml() and toAst()). Parser-behavior toggles: noIndentedCodeBlocks, permissiveAtxHeadings, collapseWhitespace. See docs/options.md for behavior and edge cases.

mdparser covers CommonMark core plus the GFM extensions. It doesn't implement the "Markdown Extra" features found in Parsedown Extra, michelf Markdown Extra, and league/commonmark's optional extensions. If you need any of the following, use league/commonmark, the most actively maintained pure-PHP option for extended Markdown:

• Definition lists (Term :: definition)
• Abbreviations (*[HTML]: ...)
• Attribute syntax ({.class #id key="val"})
• Permalink anchor markup (we emit heading id slugs; we don't inject the inner <a class="anchor"> element GitHub uses for permalinks)
• Table of contents
• YAML front matter
• Mentions (@user)
• Emoji (:smile:)
• Fenced admonition containers (::: warning); GitHub-style > [!NOTE] alert blocks are supported via Options::admonitions, and are on by default in Options::github()

The parser's own working memory comes from libc rather than Zend MM, so memory_limit never sees it. In measured release builds, [-dense input used about 76-87 bytes of parser state per input byte, and >-dense input about 45-52 bytes. Without a parse budget, a 16 MiB [-dense input can request more than 1 GiB.

mdparser.parse_memory_limit caps what a single parse may hold, defaulting to 128M. Crossing it throws MdParser\Exception. The setting is PHP_INI_ALL, takes the usual 128M / 1G shorthand, and treats an empty value as the default 128M; explicit 0 or any negative value is unlimited. With the limit off, a 256 MiB [-dense input could ask libc for roughly 19-22 GiB at the measured per-byte rate. Raise the limit if you render very large documents; lower it if you render untrusted Markdown in long-lived workers. Rendered output is separate and stays under memory_limit.

Options::unsafe = true passes raw HTML through verbatim instead of escaping or stripping it. Use it only for input you own or a pipeline you trust. headingAnchors and nofollowLinks run in-stream as md4c parses the source, so they touch only Markdown-derived nodes. Raw HTML is emitted verbatim and never rewritten:

• Heading anchors apply to Markdown headings only. A # heading gets an id such as user-content-heading; links to generated headings must use the prefixed fragment (#user-content-heading). A raw <h1>x</h1> block (possible under unsafe: true, tagfilter: false) is emitted untouched and gets no id, so it never collides with a later Markdown heading that has the same text.
• nofollowLinks applies to Markdown links only. Inline links, reference links, and autolinks get rel="nofollow noopener noreferrer"; in-document fragment anchors (href="#...", including footnote references and backrefs) are skipped. A raw <a href="..."> passes through verbatim. Sanitize raw HTML yourself if you allow it.

Parser::toXml() and Parser::toAst() return structural representations of the parsed document. html_block / html_inline literals are preserved byte-for-byte (XML-escaped in toXml()); link and image URLs and titles are entity-decoded but not scheme-filtered. The unsafe, tagfilter, and URL-scheme defenses don't make these outputs safe to turn back into HTML. If you build HTML from XML or AST data, apply a URL scheme allowlist before emitting href, and run html_block / html_inline literal text through a sanitizer. See docs/ast.md for examples.

Companion native PHP extensions:

• php_excel: native Excel I/O via LibXL. 7-10× faster than PhpSpreadsheet, full XLS/XLSX with formulas, formatting, and styling.
• php_clickhouse: native ClickHouse client speaking the wire protocol directly. Picks up where SeasClick left off.
• pdo_duckdb: PDO driver for DuckDB, analytical SQL in your PHP stack.
• fastjson: drop-in faster ext/json, backed by yyjson. 6× encode, 2.7× decode, 5× validate.
• phpser: decoder-optimized binary serializer for cache workloads. Faster than igbinary on packed numerics and DTO batches.
• fast_uuid: high-throughput UUID generation (v1/v4/v7), batched CSPRNG and SIMD hex formatter, ramsey-compatible API.
• fastchart: native chart-rendering extension. 38 chart types behind one fluent OO API, SVG-canonical with PNG/JPG/WebP and optional PDF output.
• statgrab: system statistics (CPU, memory, disk, network) via libstatgrab, no parsing /proc by hand.
• phonetic: native phonetic name matching (Double Metaphone, Beider-Morse, Daitch-Mokotoff, NYSIIS, Match Rating), the encoders PHP core lacks.

The launch post covers background, design rationale, and benchmark methodology: mdparser: A Native CommonMark + GFM Parser for PHP.

• Wrapper code (mdparser*.c, php_mdparser.h) under BSD 3-Clause.
• Embedded md4c sources under the MIT license. See LICENSE for aggregated notices.

Follow @iliaa on X • Blog • If this sped up your stack, ⭐ star it!