Document
Electronic Publication is a document format commonly identified by .epub. Use the listed signatures, MIME types, and structure notes to validate files beyond the extension.
50 4B 03 04 PK..SIGNATURE = bytes.fromhex("504b0304")
OFFSET = 0
def is_epub(path: str) -> bool:
with open(path, "rb") as f:
f.seek(OFFSET)
head = f.read(len(SIGNATURE))
return head == SIGNATUREconst SIGNATURE = [0x50, 0x4b, 0x03, 0x04];
const OFFSET = 0;
// bytes: a Uint8Array / Buffer holding the start of the file
export function isEpub(bytes) {
return SIGNATURE.every((byte, i) => bytes[OFFSET + i] === byte);
}package fileid
import "bytes"
var isepubSignature = []byte{0x50, 0x4b, 0x03, 0x04}
const isepubOffset = 0
func IsEpub(b []byte) bool {
end := isepubOffset + len(isepubSignature)
if len(b) < end {
return false
}
return bytes.Equal(b[isepubOffset:end], isepubSignature)
}const SIGNATURE: &[u8] = &[0x50, 0x4b, 0x03, 0x04];
const OFFSET: usize = 0;
fn is_epub(bytes: &[u8]) -> bool {
bytes.get(OFFSET..OFFSET + SIGNATURE.len()) == Some(SIGNATURE)
}<?php
$signature = "\x50\x4b\x03\x04";
$offset = 0;
function is_epub(string $bytes): bool {
global $signature, $offset;
return substr($bytes, $offset, strlen($signature)) === $signature;
}Electronic Publication 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 EPUB is a Electronic Publication sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
01-blue-sky.epub46b713c4a852927e9b7e527624b0ab692577b4997922ec00c659d8b9bcfcd6b4Flower Garden EPUB is a Electronic Publication sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
02-flower-garden.epub9791254a0bfa525c943bf5010a12ef46d9d98d05eae4d796995c8b44ebcfc75eNavy Blue Sky EPUB is a Electronic Publication sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
03-navy-blue-sky.epub61dc9c961f56a3dee8f0e07f18b02291665f89c10f43a1bcd8b041a079046397Nature of the Sky EPUB is a Electronic Publication sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
04-nature-sky.epub8a59b26f29daba3a1411930278966a8fc23e55347660feb0691cd71bfc925043Sky Landscape EPUB is a Electronic Publication sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
05-sky-landscape.epub32db1dc4da5dca8a666921a1f7413fc1090cb6329e98b4bd4575642ab250ac90Starry Sky EPUB is a Electronic Publication sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
06-starry-sky.epub30f23026c4b6cba65b1675ebacb89ba9f823f301581684587dee1ea093a072faBlue Night Sky EPUB is a Electronic Publication sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
07-blue-night-sky.epub6784065f85709a8f8a2a8b3d99838197c0a29427cee8322139c02c6b7828949eHibiscus Flower EPUB is a Electronic Publication sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
08-hibiscus-flower.epub93e32496707477839860c7552adbcf0229203644378c63bb19158a85ae02b188Arctic Sky EPUB is a Electronic Publication sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
09-arctic-sky.epub43e7c963fd298b81078da605951e5ca8b4a2b0feb11118af433340ae4ba8e4c6Sunset Rays EPUB is a Electronic Publication sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
10-sunset-rays.epubccd1352fd410f4f0ee556137468c1d328ac99cb725c21ab9055d68fd176cfd04NASA Blue Marble EPUB is a Electronic Publication 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.epubd5766b911a2b93a869d32ba1863e72403f8e0e245fcbb08b81f96914e338c511Electronic Publication files begin with the byte signature 50 4B 03 04 ("PK.."). Detect the format by reading these leading bytes rather than trusting the file extension alone.
The MIME type for Electronic Publication is application/epub+zip.
Electronic Publication files use the .epub extension. The extension is a convention only and does not guarantee the file contents, so combine it with signature and structure checks.