Document
Markdown is a document format commonly identified by .md, .markdown. Use the listed signatures, MIME types, and structure notes to validate files beyond the extension.
23 20 # SIGNATURE = bytes.fromhex("2320")
OFFSET = 0
def is_md(path: str) -> bool:
with open(path, "rb") as f:
f.seek(OFFSET)
head = f.read(len(SIGNATURE))
return head == SIGNATUREconst SIGNATURE = [0x23, 0x20];
const OFFSET = 0;
// bytes: a Uint8Array / Buffer holding the start of the file
export function isMd(bytes) {
return SIGNATURE.every((byte, i) => bytes[OFFSET + i] === byte);
}package fileid
import "bytes"
var ismdSignature = []byte{0x23, 0x20}
const ismdOffset = 0
func IsMd(b []byte) bool {
end := ismdOffset + len(ismdSignature)
if len(b) < end {
return false
}
return bytes.Equal(b[ismdOffset:end], ismdSignature)
}const SIGNATURE: &[u8] = &[0x23, 0x20];
const OFFSET: usize = 0;
fn is_md(bytes: &[u8]) -> bool {
bytes.get(OFFSET..OFFSET + SIGNATURE.len()) == Some(SIGNATURE)
}<?php
$signature = "\x23\x20";
$offset = 0;
function is_md(string $bytes): bool {
global $signature, $offset;
return substr($bytes, $offset, strlen($signature)) === $signature;
}Markdown is used for data exchange, imports, exports, parser testing, and validation workflows. Encoding, delimiters, versions, and container structure often change implementation behavior.
Document formats may include scripts, attachments, macros, or external references. Sandbox previews and conversions, and avoid opening untrusted files directly.
11 samples help test leading-byte detection, parser errors, upload limits, and download behavior.
Blue Sky MD is a Markdown sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
01-blue-sky.mde601110dd647a3e36a5066a3134ae6203cf137dafc0930c171d3becd6c2b08d0Flower Garden MD is a Markdown sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
02-flower-garden.md958f31e5bc3971ec7e64fcc6d462cddeb33b65a7d2e05c3936403964107ad21dNavy Blue Sky MD is a Markdown sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
03-navy-blue-sky.md557cca18ab0d22632b3864bf6ed6c4bb6240bc27e04d8b16e8e94b6ef62f0413Nature of the Sky MD is a Markdown sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
04-nature-sky.md7c772e89e19c32f13646aeb63be3f340758fc2b87b53d0c24bd53e0d09c229d3Sky Landscape MD is a Markdown sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
05-sky-landscape.md40c0f744371b70943b0dbad46bdf09a73daf9c298fc36b9fffad687a401c3c4cStarry Sky MD is a Markdown sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
06-starry-sky.mdedb76a5c7e82de5990d771696c4e4a49d72cfba7b348e46793edb1ea96d5ae21Blue Night Sky MD is a Markdown sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
07-blue-night-sky.md84a83bff6547257be087824787d0108814161232f3ad0745fd723433cf56fd0cHibiscus Flower MD is a Markdown sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
08-hibiscus-flower.md3edfe6b56fde0f49b507896a893cfdb6af542339336e173f1c1f08f6f1560861Arctic Sky MD is a Markdown sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
09-arctic-sky.md14000757d95cb6147b1977862f2002872ed6902ff9c9a3b2d330a30a28d1460bSunset Rays MD is a Markdown sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
10-sunset-rays.md631007f568fea9750956728b96f424cbd5a136f8e89677b7c0344e184b0edbcbNASA Blue Marble MD is a Markdown sample based on NASA Image and Video Library. It can be used to test downloads, parsers, previews, and file type detection.
nasa-blue-marble-2012-east.md6fc911149dd9d9ef1df0cfbe645a0e8b82b60cb73a1b580ff894a26d8d2f4da7Markdown files begin with the byte signature 23 20 ("# "). Detect the format by reading these leading bytes rather than trusting the file extension alone.
The MIME type for Markdown is text/markdown.
Markdown files use the .md, .markdown extension. The extension is a convention only and does not guarantee the file contents, so combine it with signature and structure checks.