Lotus 1-2-3 spreadsheet
application/vnd.lotus-1-2-3;version=3
Magic Bytes
Offset: 0
00 00 1A 00 00 10 04 00
The WK3 file format is a proprietary spreadsheet structure developed by the Lotus Development Corporation for version 3.x of the Lotus 1-2-3 software suite. It facilitates the storage of numerical data, complex formulas, and macro instructions within a three-dimensional, grid-based workbook environment. As a legacy format largely superseded by modern XML-based standards, it remains relevant primarily for data archiving and historical recovery within older enterprise environments.
Validation Code
How to validate .wk3 files in Python
Python
def is_wk3(file_path: str) -> bool:
"""Check if file is a valid WK3 by magic bytes."""
signature = bytes([0x00, 0x00, 0x1A, 0x00, 0x00, 0x10, 0x04, 0x00])
with open(file_path, "rb") as f:
return f.read(8) == signatureHow to validate .wk3 files in Node.js
Node.js
function isWK3(buffer: Buffer): boolean {
const signature = Buffer.from([0x00, 0x00, 0x1A, 0x00, 0x00, 0x10, 0x04, 0x00]);
return buffer.subarray(0, 8).equals(signature);
}
Go
func IsWK3(data []byte) bool {
signature := []byte{0x00, 0x00, 0x1A, 0x00, 0x00, 0x10, 0x04, 0x00}
if len(data) < 8 {
return false
}
return bytes.Equal(data[:8], signature)
}API Endpoint
GET
/api/v1/wk3
curl https://filesignature.org/api/v1/wk3