{"success":true,"data":{"ext":"xlsx","name":"Microsoft Office Open XML Format","description":"Microsoft Excel Spreadsheet (XLSX) is a spreadsheet file format based on the Microsoft Office Open XML standard, developed by Microsoft and standardized by Ecma International and ISO/IEC. It is used for worksheets, tables, formulas, charts, and business data exchange in Microsoft Excel and compatible office applications. The format is generally safe, but like other document containers it can include macros in related formats or embedded content from untrusted sources.","mime":["application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"],"risk_level":"Safe","signatures":[{"hex":"50 4B 03 04","offset":0,"sources":[{"name":"Wikipedia","url":"https://en.wikipedia.org/wiki/List_of_file_signatures"}]},{"hex":"50 4B 05 06","offset":0,"sources":[{"name":"Wikipedia","url":"https://en.wikipedia.org/wiki/List_of_file_signatures"}]},{"hex":"50 4B 07 08","offset":0,"sources":[{"name":"Wikipedia","url":"https://en.wikipedia.org/wiki/List_of_file_signatures"}]},{"hex":"50 4B 03 04 14 00 06 00","offset":0,"sources":[{"name":"Gary Kessler","url":"https://www.garykessler.net/library/file_sigs_GCK_latest.html"}]}],"related":["ods","ots","wks","xls","xlt","docx"],"usage":{"python":"def is_xlsx(file_path: str) -> bool:\n    \"\"\"Check if file is a valid XLSX by magic bytes.\"\"\"\n    signature = bytes([0x50, 0x4B, 0x03, 0x04])\n    with open(file_path, \"rb\") as f:\n        return f.read(4) == signature","node":"function isXLSX(buffer: Buffer): boolean {\n  const signature = Buffer.from([0x50, 0x4B, 0x03, 0x04]);\n  return buffer.subarray(0, 4).equals(signature);\n}","go":"func IsXLSX(data []byte) bool {\n    signature := []byte{0x50, 0x4B, 0x03, 0x04}\n    if len(data) < 4 {\n        return false\n    }\n    return bytes.Equal(data[:4], signature)\n}"},"category":"Office"}}