Arc
Single-file ZIP
Single-file ZIP is a ZIP Archive sample generated for file format testing. It can be used to test downloads, parsers, previews, and file type detection.
single-file.zipType Sample
130 B DownloadArchive
ZIP ZIP Archive
ZIP Archive is a archive format commonly identified by .zip. Use the listed signatures, MIME types, and structure notes to validate files beyond the extension.
Extensions .zip
MIME application/zip
Magic numbers
Analyze your fileoffset 0 ZIP Archive leading signature
50 4B 03 04 PK..offset 0 ZIP Archive leading signature
50 4B 05 06 PK..offset 0 ZIP Archive leading signature
50 4B 07 08 PK..Structure
- Local file headers
- Compressed file data
- Central directory
- End of central directory
Caveats
- Do not trust the extension alone. Check the MIME type, the first bytes such as 50 4B 03 04, and format-specific structure when possible.
- Container formats and damaged files can share the same opening bytes, so deeper validation may be required for production upload, preview, or conversion flows.
Detection example
SIGNATURE = bytes.fromhex("504b0304")
OFFSET = 0
def is_zip(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 isZip(bytes) {
return SIGNATURE.every((byte, i) => bytes[OFFSET + i] === byte);
}package fileid
import "bytes"
var iszipSignature = []byte{0x50, 0x4b, 0x03, 0x04}
const iszipOffset = 0
func IsZip(b []byte) bool {
end := iszipOffset + len(iszipSignature)
if len(b) < end {
return false
}
return bytes.Equal(b[iszipOffset:end], iszipSignature)
}const SIGNATURE: &[u8] = &[0x50, 0x4b, 0x03, 0x04];
const OFFSET: usize = 0;
fn is_zip(bytes: &[u8]) -> bool {
bytes.get(OFFSET..OFFSET + SIGNATURE.len()) == Some(SIGNATURE)
}<?php
$signature = "\x50\x4b\x03\x04";
$offset = 0;
function is_zip(string $bytes): bool {
global $signature, $offset;
return substr($bytes, $offset, strlen($signature)) === $signature;
}Practical usage
Use cases
ZIP Archive is used for compression, extraction, backups, attachments, and multi-file inspection. Validate paths, file counts, compressed size, and extracted size before unpacking.
Common detection mistakes
- The .zip extension alone does not prove the file contents. Upload and conversion flows should combine extension, MIME type, leading bytes, and format-specific structure checks.
- ZIP Archive can start with signatures such as 50 4B 03 04 or 50 4B 05 06 or 50 4B 07 08, but related containers and damaged files may require additional validation.
Security notes
Archives can contain zip-slip paths, excessive expansion, hidden files, and double extensions. Normalize extraction paths and enforce file count and size limits.
Using samples
11 samples help test leading-byte detection, parser errors, upload limits, and download behavior.
Sample files
11 / 11 filesArc
Empty ZIP
Empty ZIP is a ZIP Archive sample generated for file format testing. It can be used to test downloads, parsers, previews, and file type detection.
empty.zipType Sample
22 B DownloadArc
Two File ZIP
Two File ZIP is a ZIP Archive sample generated for file format testing. It can be used to test downloads, parsers, previews, and file type detection.
two-files.zipType Sample
264 B DownloadArc
Blue Sky ZIP
Blue Sky ZIP is a ZIP Archive sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
01-blue-sky.zipType Sample
675 B SHA-256
406899035ac2a5ebd7641aaf09b0026caf34ae6414f224801a2df79888baab21Arc
Flower Garden ZIP
Flower Garden ZIP is a ZIP Archive sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
02-flower-garden.zipType Sample
1.2 KB SHA-256
9ff8454befd465893ed4f21427fb53aff3b830d7501e125445d32b27e6d71477Arc
Navy Blue Sky ZIP
Navy Blue Sky ZIP is a ZIP Archive sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
03-navy-blue-sky.zipType Sample
1.6 KB SHA-256
821a889e4ca078ef99efa381eaf06128e7859bf439ee3eb53f099eea43af5b13Arc
Nature of the Sky ZIP
Nature of the Sky ZIP is a ZIP Archive sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
04-nature-sky.zipType Sample
2.1 KB SHA-256
4b7eef406dfa9120a46e419abf15f8d5fdd4b59f82e41548e895b3859d1c81eeArc
Sky Landscape ZIP
Sky Landscape ZIP is a ZIP Archive sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
05-sky-landscape.zipType Sample
2.9 KB SHA-256
1efa3a18f71d6235167237cdc8611dbacd9812b6aac86d5fdac2e87843a0a96fArc
Starry Sky ZIP
Starry Sky ZIP is a ZIP Archive sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
06-starry-sky.zipType Sample
2.9 KB SHA-256
9dea35b1174a734275f911257297b00a3f7269459b6f99becfc061f3e4cfeed1Arc
Blue Night Sky ZIP
Blue Night Sky ZIP is a ZIP Archive sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
07-blue-night-sky.zipType Sample
3.7 KB SHA-256
ae59106122a39caf2142ab9cb6947522d55b5afeba9d8d89fa63d5801fcb752bArc
NASA Blue Marble ZIP
NASA Blue Marble ZIP is a ZIP Archive 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.zipType Sample
10 KB SHA-256
527dd0ee5ce84bfea705fa242f5a9bd38c951d91f9c2c37f79ab8766612530dbFrequently asked questions
What is the magic number (file signature) of ZIP Archive?
ZIP Archive files begin with the byte signature 50 4B 03 04 ("PK..") or 50 4B 05 06 ("PK..") or 50 4B 07 08 ("PK.."). Detect the format by reading these leading bytes rather than trusting the file extension alone.
What is the MIME type of ZIP Archive?
The MIME type for ZIP Archive is application/zip.
What file extension does ZIP Archive use?
ZIP Archive files use the .zip extension. The extension is a convention only and does not guarantee the file contents, so combine it with signature and structure checks.