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PK3 (.pk3)

.pk3 file signature | application/octet-stream

zip file formatand formats based on it, such asEPUB,JAR,ODF,OOXML

Safe

Magic Bytes

Offset 0
50 4B 03 04 50 4B 05 06 50 4B 07 08

Sources: Wikipedia

Extension

.pk3

MIME Type

application/octet-stream

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .pk3 files in Python

Python 
def is_pk3(file_path: str) -> bool:
    """Check if file is a valid PK3 by magic bytes."""
    signature = bytes([0x50, 0x4B, 0x03, 0x04, 0x50, 0x4B, 0x05, 0x06, 0x50, 0x4B, 0x07, 0x08])
    with open(file_path, "rb") as f:
        return f.read(12) == signature

How to validate .pk3 files in Node.js

Node.js 
function isPK3(buffer: Buffer): boolean {
  const signature = Buffer.from([0x50, 0x4B, 0x03, 0x04, 0x50, 0x4B, 0x05, 0x06, 0x50, 0x4B, 0x07, 0x08]);
  return buffer.subarray(0, 12).equals(signature);
}

How to validate .pk3 files in Go

Go 
func IsPK3(data []byte) bool {
    signature := []byte{0x50, 0x4B, 0x03, 0x04, 0x50, 0x4B, 0x05, 0x06, 0x50, 0x4B, 0x07, 0x08}
    if len(data) < 12 {
        return false
    }
    return bytes.Equal(data[:12], signature)
}

API Endpoint

GET /api/v1/pk3
curl https://filesignature.org/api/v1/pk3

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .pk3 file?

A .pk3 file is a PK3 file. zip file formatand formats based on it, such asEPUB,JAR,ODF,OOXML

What are the magic bytes for .pk3 files?

The magic bytes for PK3 files are 50 4B 03 04 50 4B 05 06 50 4B 07 08 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .pk3 file?

To validate a .pk3 file, read the first bytes of the file and compare them against the known magic bytes (50 4B 03 04 50 4B 05 06 50 4B 07 08) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .pk3 files?

There is no officially registered MIME type for .pk3 files. Systems typically use application/octet-stream as a generic fallback when handling this format.

Is it safe to open .pk3 files?

PK3 (.pk3) files are generally safe to open. They are classified as low risk because they primarily contain data rather than executable code. However, always ensure files come from a trusted source.