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OTM (.otm)

.otm file signature | application/vnd.oasis.opendocument.text-master

OpenDocument Text Master (OTM) is a document template and master document format defined and maintained by OASIS as part of the OpenDocument family. It is used in office suites such as LibreOffice and Apache OpenOffice for assembling long documents, managing shared styles, and combining multiple content sources into a single text master file. As a legacy OpenDocument component, it is generally safe, though files from untrusted sources should still be opened cautiously.

Safe

Magic Bytes

Offset 0
50 4B

Sources: Apache Tika

Extension

.otm

MIME Type

application/vnd.oasis.opendocument.text-master

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .otm files in Python

Python 
def is_otm(file_path: str) -> bool:
    """Check if file is a valid OTM by magic bytes."""
    signature = bytes([0x50, 0x4B])
    with open(file_path, "rb") as f:
        return f.read(2) == signature

How to validate .otm files in Node.js

Node.js 
function isOTM(buffer: Buffer): boolean {
  const signature = Buffer.from([0x50, 0x4B]);
  return buffer.subarray(0, 2).equals(signature);
}

How to validate .otm files in Go

Go 
func IsOTM(data []byte) bool {
    signature := []byte{0x50, 0x4B}
    if len(data) < 2 {
        return false
    }
    return bytes.Equal(data[:2], signature)
}

API Endpoint

GET /api/v1/otm
curl https://filesignature.org/api/v1/otm

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .otm file?

A .otm file is identified by the magic bytes 50 4B at byte offset 0. OpenDocument Text Master (OTM) is a document template and master document format defined and maintained by OASIS as part of the OpenDocument family. It is used in office suites such as LibreOffice and Apache OpenOffice for assembling long documents, managing shared styles, and combining multiple content sources into a single text master file. As a legacy OpenDocument component, it is generally safe, though files from untrusted sources should still be opened cautiously.

What are the magic bytes for .otm files?

The magic bytes for OTM files are 50 4B at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .otm file?

To validate a .otm file, read the first bytes of the file and compare them against the known magic bytes (50 4B) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .otm files?

The primary MIME type for .otm files is application/vnd.oasis.opendocument.text-master.

Is it safe to open .otm files?

OTM (.otm) 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.