JXL
image/jxl
Magic Bytes
Offset: 0
00 00 00 0C 4A 58 4C 20 0D 0A 87 0A
JPEG XL is a modern raster graphics file format developed by the Joint Photographic Experts Group as a universal replacement for existing image standards. It is primarily used for efficient web delivery and professional photography, offering both lossless and lossy compression with reversible JPEG transcoding capabilities. Standardized as ISO/IEC 18181, the format is royalty-free and presents a low security risk, focusing on high visual fidelity rather than complex active content features.
Validation Code
How to validate .jxl files in Python
Python
def is_jxl(file_path: str) -> bool:
"""Check if file is a valid JXL by magic bytes."""
signature = bytes([0x00, 0x00, 0x00, 0x0C, 0x4A, 0x58, 0x4C, 0x20, 0x0D, 0x0A, 0x87, 0x0A])
with open(file_path, "rb") as f:
return f.read(12) == signatureHow to validate .jxl files in Node.js
Node.js
function isJXL(buffer: Buffer): boolean {
const signature = Buffer.from([0x00, 0x00, 0x00, 0x0C, 0x4A, 0x58, 0x4C, 0x20, 0x0D, 0x0A, 0x87, 0x0A]);
return buffer.subarray(0, 12).equals(signature);
}
Go
func IsJXL(data []byte) bool {
signature := []byte{0x00, 0x00, 0x00, 0x0C, 0x4A, 0x58, 0x4C, 0x20, 0x0D, 0x0A, 0x87, 0x0A}
if len(data) < 12 {
return false
}
return bytes.Equal(data[:12], signature)
}API Endpoint
GET
/api/v1/jxl
curl https://filesignature.org/api/v1/jxl