Skip to content

ArcMap GIS project file magic bytes (.mxd)

.mxd file signature: D0 CF 11 E0 A1 B1 1A E1 | application/octet-stream

ArcMap GIS project file is a document format used by Esri, the company behind ArcGIS, to store map composition and layer settings for ArcMap projects. It is used to organize geographic data, cartographic layouts, symbology, and map metadata in desktop GIS workflows and map production. The format is generally safe to open, but it is tied to the legacy ArcMap application and may not be fully supported in newer ArcGIS versions.

Safe

Magic Bytes

Offset 0
D0 CF 11 E0 A1 B1 1A E1

Sources: Gary Kessler

Extension

.mxd

MIME Type

application/octet-stream

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .mxd files in Python

Python 
def is_mxd(file_path: str) -> bool:
    """Check if file is a valid MXD 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 .mxd files in Node.js

Node.js 
function isMXD(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 .mxd files in Go

Go 
func IsMXD(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/mxd
curl https://filesignature.org/api/v1/mxd

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .mxd file?

A .mxd file is an ArcMap GIS project file. ArcMap GIS project file is a document format used by Esri, the company behind ArcGIS, to store map composition and layer settings for ArcMap projects. It is used to organize geographic data, cartographic layouts, symbology, and map metadata in desktop GIS workflows and map production. The format is generally safe to open, but it is tied to the legacy ArcMap application and may not be fully supported in newer ArcGIS versions.

What are the magic bytes for .mxd files?

The magic bytes for ArcMap GIS project file (.mxd) files are D0 CF 11 E0 A1 B1 1A E1 at byte offset 0. These bytes identify the file format more reliably than the extension alone.

How do I validate a .mxd file?

To validate a .mxd 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 .mxd files?

There is no officially registered MIME type for .mxd files. Systems typically use application/octet-stream as a generic fallback when handling this format.

Is it safe to open .mxd files?

ArcMap GIS project file (.mxd) 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.