Arc
Small GZIP
Small GZIP is a GZIP Compressed Data sample generated for file format testing. It can be used to test downloads, parsers, previews, and file type detection.
small.txt.gzType Sample
34 B DownloadArchive
GZ GZIP Compressed Data
GZIP Compressed Data is a archive format commonly identified by .gz, .gzip. Use the listed signatures, MIME types, and structure notes to validate files beyond the extension.
Extensions .gz, .gzip
MIME application/gzip
Magic numbers
Analyze your fileoffset 0 GZIP Compressed Data leading signature
1F 8B 08 ...Structure
- Header
- Optional metadata fields
- Compressed deflate blocks
- CRC32
- Input size
Caveats
- Do not trust the extension alone. Check the MIME type, the first bytes such as 1F 8B 08, 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("1f8b08")
OFFSET = 0
def is_gz(path: str) -> bool:
with open(path, "rb") as f:
f.seek(OFFSET)
head = f.read(len(SIGNATURE))
return head == SIGNATUREconst SIGNATURE = [0x1f, 0x8b, 0x08];
const OFFSET = 0;
// bytes: a Uint8Array / Buffer holding the start of the file
export function isGz(bytes) {
return SIGNATURE.every((byte, i) => bytes[OFFSET + i] === byte);
}package fileid
import "bytes"
var isgzSignature = []byte{0x1f, 0x8b, 0x08}
const isgzOffset = 0
func IsGz(b []byte) bool {
end := isgzOffset + len(isgzSignature)
if len(b) < end {
return false
}
return bytes.Equal(b[isgzOffset:end], isgzSignature)
}const SIGNATURE: &[u8] = &[0x1f, 0x8b, 0x08];
const OFFSET: usize = 0;
fn is_gz(bytes: &[u8]) -> bool {
bytes.get(OFFSET..OFFSET + SIGNATURE.len()) == Some(SIGNATURE)
}<?php
$signature = "\x1f\x8b\x08";
$offset = 0;
function is_gz(string $bytes): bool {
global $signature, $offset;
return substr($bytes, $offset, strlen($signature)) === $signature;
}Practical usage
Use cases
GZIP Compressed Data 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 .gz / .gzip extension alone does not prove the file contents. Upload and conversion flows should combine extension, MIME type, leading bytes, and format-specific structure checks.
- GZIP Compressed Data can start with signatures such as 1F 8B 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 GZIP
Empty GZIP is a GZIP Compressed Data sample generated for file format testing. It can be used to test downloads, parsers, previews, and file type detection.
empty.gzType Sample
20 B DownloadArc
Blue Sky TXT.GZ
Blue Sky TXT.GZ is a GZIP Compressed Data sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
01-blue-sky.txt.gzType Sample
158 B SHA-256
bd339e2f6ecde312ad681f2dbadacb5fa40f1272a989a46e48b6ae5412d3a86bArc
Flower Garden TXT.GZ
Flower Garden TXT.GZ is a GZIP Compressed Data sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
02-flower-garden.txt.gzType Sample
192 B SHA-256
e347f058c65e3a70b8ebd7eec0df68eb345f88f13d96ff61c5ad4a6a0d3e3c14Arc
Navy Blue Sky TXT.GZ
Navy Blue Sky TXT.GZ is a GZIP Compressed Data sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
03-navy-blue-sky.txt.gzType Sample
184 B SHA-256
f0ffbb194ac00c32c155e2ae64f5b11125fd4ade8bf8405f9cc2df876936eb66Arc
Nature of the Sky TXT.GZ
Nature of the Sky TXT.GZ is a GZIP Compressed Data sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
04-nature-sky.txt.gzType Sample
178 B SHA-256
26c4f012b0eb40487581dbbf95c2c6629a32b6a21aa83d47f2124794a548beb2Arc
Sky Landscape TXT.GZ
Sky Landscape TXT.GZ is a GZIP Compressed Data sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
05-sky-landscape.txt.gzType Sample
197 B SHA-256
6e7bb216870b8130a07481215de2dc4f3e442b2a1bc94254e3acfbbf86fef4baArc
Starry Sky TXT.GZ
Starry Sky TXT.GZ is a GZIP Compressed Data sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
06-starry-sky.txt.gzType Sample
179 B SHA-256
5def2c45c82871e416c64efa4e58e1367bb3b22fac3f882b0cad04eb5c83fce6Arc
Blue Night Sky TXT.GZ
Blue Night Sky TXT.GZ is a GZIP Compressed Data sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
07-blue-night-sky.txt.gzType Sample
181 B SHA-256
e944abd9432452504192795441c70d4d411d2fb2d157704957a6e435e9f4d6d0Arc
Hibiscus Flower TXT.GZ
Hibiscus Flower TXT.GZ is a GZIP Compressed Data sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
08-hibiscus-flower.txt.gzType Sample
204 B SHA-256
e8d823308dd8f6c889030ff57aa5990f981864988e88b76436b08dc084bec84dArc
NASA Blue Marble TXT.GZ
NASA Blue Marble TXT.GZ is a GZIP Compressed Data 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.txt.gzType Sample
235 B SHA-256
4a3d9989895a7d7cfb77d26c5369c6d539ad763fa942f4f3c16ee79910dfe7d1Frequently asked questions
What is the magic number (file signature) of GZIP Compressed Data?
GZIP Compressed Data files begin with the byte signature 1F 8B 08 ("..."). Detect the format by reading these leading bytes rather than trusting the file extension alone.
What is the MIME type of GZIP Compressed Data?
The MIME type for GZIP Compressed Data is application/gzip.
What file extension does GZIP Compressed Data use?
GZIP Compressed Data files use the .gz, .gzip extension. The extension is a convention only and does not guarantee the file contents, so combine it with signature and structure checks.