Web Open Font Format
application/octet-stream
Magic Bytes
Offset: 0
77 4F 46 46
The Web Open Font Format (WOFF) is a font packaging standard developed by Mozilla, Microsoft, and Opera, currently maintained by the World Wide Web Consortium. It wraps TrueType and OpenType fonts in a compressed container to facilitate the efficient delivery of custom typography for web browsers and digital interfaces. Although largely superseded by WOFF2, this format remains a secure, stable choice for broad compatibility across legacy systems without introducing significant security vulnerabilities to the end user.
Validation Code
How to validate .woff files in Python
def is_woff(file_path: str) -> bool:
"""Check if file is a valid WOFF by magic bytes."""
signature = bytes([0x77, 0x4F, 0x46, 0x46])
with open(file_path, "rb") as f:
return f.read(4) == signatureHow to validate .woff files in Node.js
function isWOFF(buffer: Buffer): boolean {
const signature = Buffer.from([0x77, 0x4F, 0x46, 0x46]);
return buffer.subarray(0, 4).equals(signature);
}How to validate .woff files in Go
func IsWOFF(data []byte) bool {
signature := []byte{0x77, 0x4F, 0x46, 0x46}
if len(data) < 4 {
return false
}
return bytes.Equal(data[:4], signature)
}API Endpoint
/api/v1/woff
curl https://filesignature.org/api/v1/woff
Related Formats
Frequently Asked Questions
What is a .woff file?
A .woff file is a Web Open Font Format file. The Web Open Font Format (WOFF) is a font packaging standard developed by Mozilla, Microsoft, and Opera, currently maintained by the World Wide Web Consortium. It wraps TrueType and OpenType fonts in a compressed container to facilitate the efficient delivery of custom typography for web browsers and digital interfaces. Although largely superseded by WOFF2, this format remains a secure, stable choice for broad compatibility across legacy systems without introducing significant security vulnerabilities to the end user.
What are the magic bytes for .woff files?
The magic bytes for Web Open Font Format files are 77 4F 46 46 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.
How do I validate a .woff file?
To validate a .woff file, read the first bytes of the file and compare them against the known magic bytes (77 4F 46 46) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .woff files?
The primary MIME type for .woff files is application/octet-stream.
Is it safe to open .woff files?
Web Open Font Format (.woff) 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.