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FH9 (.fh9)

.fh9 file signature | image/x-freehand

Safe

Magic Bytes

Offset 0
41 47 44 32

Sources: Apache Tika

All Known Signatures

6 signature variants are documented for .fh9 files across multiple sources.

Hex Signature Offset Sources
41 47 44 32 0 Apache Tika
41 47 44 33 0 Apache Tika
41 47 44 34 0 Apache Tika
46 72 65 65 48 61 6E 64 31 30 0 Apache Tika
46 72 65 65 48 61 6E 64 31 31 0 Apache Tika
46 72 65 65 48 61 6E 64 31 32 0 Apache Tika

Extension

.fh9

MIME Type

image/x-freehand

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .fh9 files in Python

Python
def is_fh9(file_path: str) -> bool:
    """Check if file is a valid FH9 by magic bytes."""
    signature = bytes([0x41, 0x47, 0x44, 0x32])
    with open(file_path, "rb") as f:
        return f.read(4) == signature

How to validate .fh9 files in Node.js

Node.js
function isFH9(buffer: Buffer): boolean {
  const signature = Buffer.from([0x41, 0x47, 0x44, 0x32]);
  return buffer.subarray(0, 4).equals(signature);
}

How to validate .fh9 files in Go

Go
func IsFH9(data []byte) bool {
    signature := []byte{0x41, 0x47, 0x44, 0x32}
    if len(data) < 4 {
        return false
    }
    return bytes.Equal(data[:4], signature)
}

API Endpoint

GET /api/v1/fh9
curl https://filesignature.org/api/v1/fh9

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .fh9 file?

A .fh9 file is a FH9 file.

What are the magic bytes for .fh9 files?

The magic bytes for FH9 files are 41 47 44 32 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .fh9 file?

To validate a .fh9 file, read the first bytes of the file and compare them against the known magic bytes (41 47 44 32) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .fh9 files?

The primary MIME type for .fh9 files is image/x-freehand.

Is it safe to open .fh9 files?

FH9 (.fh9) 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.