XLR (.xlr)

.xlr file signature | application/x-tika-msworks-spreadsheet

Microsoft Works Spreadsheet (XLR) is a legacy spreadsheet file format created by Microsoft for the Works productivity suite. It was used for storing worksheets, formulas, charts, and tabular data in personal and small-office applications, and is now primarily encountered in archived or migrated documents. The format is generally safe to open, but support in modern software is limited, so files may require conversion for reliable access.

Safe

Magic Bytes

Offset 0


              D0 CF 11 E0 A1 B1 1A E1

Sources: Apache Tika

Extension

.xlr

MIME Type

application/x-tika-msworks-spreadsheet

Byte Offset

Risk Level

Safe

Validation Code

How to validate .xlr files in Python

Python

def is_xlr(file_path: str) -> bool:
    """Check if file is a valid XLR by magic bytes."""
    signature = bytes([0xD0, 0xCF, 0x11, 0xE0, 0xA1, 0xB1, 0x1A, 0xE1])
    with open(file_path, "rb") as f:
        return f.read(8) == signature

How to validate .xlr files in Node.js

Node.js

function isXLR(buffer: Buffer): boolean {
  const signature = Buffer.from([0xD0, 0xCF, 0x11, 0xE0, 0xA1, 0xB1, 0x1A, 0xE1]);
  return buffer.subarray(0, 8).equals(signature);
}

How to validate .xlr files in Go

func IsXLR(data []byte) bool {
    signature := []byte{0xD0, 0xCF, 0x11, 0xE0, 0xA1, 0xB1, 0x1A, 0xE1}
    if len(data) < 8 {
        return false
    }
    return bytes.Equal(data[:8], signature)
}

API Endpoint

GET /api/v1/xlr


              curl https://filesignature.org/api/v1/xlr

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .xlr file?

A .xlr file is identified by the magic bytes D0 CF 11 E0 A1 B1 1A E1 at byte offset 0. Microsoft Works Spreadsheet (XLR) is a legacy spreadsheet file format created by Microsoft for the Works productivity suite. It was used for storing worksheets, formulas, charts, and tabular data in personal and small-office applications, and is now primarily encountered in archived or migrated documents. The format is generally safe to open, but support in modern software is limited, so files may require conversion for reliable access.

What are the magic bytes for .xlr files?

The magic bytes for XLR files are D0 CF 11 E0 A1 B1 1A E1 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .xlr file?

To validate a .xlr file, read the first bytes of the file and compare them against the known magic bytes (D0 CF 11 E0 A1 B1 1A E1) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .xlr files?

The primary MIME type for .xlr files is application/x-tika-msworks-spreadsheet.

Is it safe to open .xlr files?

XLR (.xlr) 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.