Doc
Small PDF
Small PDF is a Portable Document Format sample generated for file format testing. It can be used to test downloads, parsers, previews, and file type detection.
small.pdfType Sample
459 B DownloadDocument
PDF Portable Document Format
Portable Document Format is a document format commonly identified by .pdf. Use the listed signatures, MIME types, and structure notes to validate files beyond the extension.
Extensions .pdf
MIME application/pdf
Magic numbers
Analyze your fileoffset 0 Portable Document Format leading signature
25 50 44 46 2D %PDF-Structure
- Header
- Body objects
- Cross-reference table or stream
- Trailer
- %%EOF
Caveats
- Do not trust the extension alone. Check the MIME type, the first bytes such as 25 50 44 46 2D, 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("255044462d")
OFFSET = 0
def is_pdf(path: str) -> bool:
with open(path, "rb") as f:
f.seek(OFFSET)
head = f.read(len(SIGNATURE))
return head == SIGNATUREconst SIGNATURE = [0x25, 0x50, 0x44, 0x46, 0x2d];
const OFFSET = 0;
// bytes: a Uint8Array / Buffer holding the start of the file
export function isPdf(bytes) {
return SIGNATURE.every((byte, i) => bytes[OFFSET + i] === byte);
}package fileid
import "bytes"
var ispdfSignature = []byte{0x25, 0x50, 0x44, 0x46, 0x2d}
const ispdfOffset = 0
func IsPdf(b []byte) bool {
end := ispdfOffset + len(ispdfSignature)
if len(b) < end {
return false
}
return bytes.Equal(b[ispdfOffset:end], ispdfSignature)
}const SIGNATURE: &[u8] = &[0x25, 0x50, 0x44, 0x46, 0x2d];
const OFFSET: usize = 0;
fn is_pdf(bytes: &[u8]) -> bool {
bytes.get(OFFSET..OFFSET + SIGNATURE.len()) == Some(SIGNATURE)
}<?php
$signature = "\x25\x50\x44\x46\x2d";
$offset = 0;
function is_pdf(string $bytes): bool {
global $signature, $offset;
return substr($bytes, $offset, strlen($signature)) === $signature;
}Practical usage
Use cases
Portable Document Format is used for data exchange, imports, exports, parser testing, and validation workflows. Encoding, delimiters, versions, and container structure often change implementation behavior.
Common detection mistakes
- The .pdf extension alone does not prove the file contents. Upload and conversion flows should combine extension, MIME type, leading bytes, and format-specific structure checks.
- Portable Document Format can start with signatures such as 25 50 44 46 2D, but related containers and damaged files may require additional validation.
Security notes
Document formats may include scripts, attachments, macros, or external references. Sandbox previews and conversions, and avoid opening untrusted files directly.
Using samples
11 samples help test leading-byte detection, parser errors, upload limits, and download behavior.
Sample files
11 / 11 filesDoc
PDF with Metadata
PDF with Metadata is a Portable Document Format sample generated for file format testing. It can be used to test downloads, parsers, previews, and file type detection.
note-with-metadata.pdfType Sample
587 B DownloadDoc
Blue Sky PDF
Blue Sky PDF is a Portable Document Format sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
01-blue-sky.pdfType Sample
591 B SHA-256
e4c697ed1efd7fc82f69d9b69461ff3d0a10ac86fab771fa9734dd6227fe58ddDoc
Flower Garden PDF
Flower Garden PDF is a Portable Document Format sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
02-flower-garden.pdfType Sample
660 B SHA-256
7d924c973b66969ea3c4fb2fc53c1bbb3ff04ce03999bc28215295aa9616c156Doc
Navy Blue Sky PDF
Navy Blue Sky PDF is a Portable Document Format sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
03-navy-blue-sky.pdfType Sample
677 B SHA-256
f4cd44f622ebdb47b094f20f038863d6ecd8e092d3e283f4b989ea579e357ebdDoc
Nature of the Sky PDF
Nature of the Sky PDF is a Portable Document Format sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
04-nature-sky.pdfType Sample
724 B SHA-256
454a460c2673d8e93f7158c851c1af39b9adfd585663bac7d59a3d24a4205e51Doc
Sky Landscape PDF
Sky Landscape PDF is a Portable Document Format sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
05-sky-landscape.pdfType Sample
798 B SHA-256
4b1fa5611d64d91b474b2373ad44df768be2e3b7a4e61bc48571fe0e1d3615e0Doc
Starry Sky PDF
Starry Sky PDF is a Portable Document Format sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
06-starry-sky.pdfType Sample
710 B SHA-256
54cf9824543461bb44d900b3dd35e263a14130365e7dd32264b8319f41e7d7adDoc
Blue Night Sky PDF
Blue Night Sky PDF is a Portable Document Format sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
07-blue-night-sky.pdfType Sample
805 B SHA-256
8bddc3e2dbfcea5f81616ead2af7e08d7b9c4de91f72a2facb3756b5898f2226Doc
Hibiscus Flower PDF
Hibiscus Flower PDF is a Portable Document Format sample based on Wikimedia Commons. It can be used to test downloads, parsers, previews, and file type detection.
08-hibiscus-flower.pdfType Sample
944 B SHA-256
6ed98d6bd8b56da3977af81b40a9f3b73b64e2fc568934488f1b3a4e6f577b81Doc
NASA Blue Marble PDF
NASA Blue Marble PDF is a Portable Document Format 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.pdfType Sample
1.4 KB SHA-256
f3368791d86a5b759647de15e92b666d9f137152aceaf457ab461304f2d9c27cFrequently asked questions
What is the magic number (file signature) of Portable Document Format?
Portable Document Format files begin with the byte signature 25 50 44 46 2D ("%PDF-"). Detect the format by reading these leading bytes rather than trusting the file extension alone.
What is the MIME type of Portable Document Format?
The MIME type for Portable Document Format is application/pdf.
What file extension does Portable Document Format use?
Portable Document Format files use the .pdf extension. The extension is a convention only and does not guarantee the file contents, so combine it with signature and structure checks.