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OLE (.tlb)

.tlb file signature | application/octet-stream

OLE, SPSS, or Visual C++ type library file

Safe

Magic Bytes

Offset 0
4D 53 46 54 02 00 01 00

Sources: Gary Kessler

Extension

.tlb

MIME Type

application/octet-stream

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .tlb files in Python

Python 
def is_tlb(file_path: str) -> bool:
    """Check if file is a valid TLB by magic bytes."""
    signature = bytes([0x4D, 0x53, 0x46, 0x54, 0x02, 0x00, 0x01, 0x00])
    with open(file_path, "rb") as f:
        return f.read(8) == signature

How to validate .tlb files in Node.js

Node.js 
function isTLB(buffer: Buffer): boolean {
  const signature = Buffer.from([0x4D, 0x53, 0x46, 0x54, 0x02, 0x00, 0x01, 0x00]);
  return buffer.subarray(0, 8).equals(signature);
}

How to validate .tlb files in Go

Go 
func IsTLB(data []byte) bool {
    signature := []byte{0x4D, 0x53, 0x46, 0x54, 0x02, 0x00, 0x01, 0x00}
    if len(data) < 8 {
        return false
    }
    return bytes.Equal(data[:8], signature)
}

API Endpoint

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

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .tlb file?

A .tlb file is a OLE file. OLE, SPSS, or Visual C++ type library file

What are the magic bytes for .tlb files?

The magic bytes for OLE files are 4D 53 46 54 02 00 01 00 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .tlb file?

To validate a .tlb file, read the first bytes of the file and compare them against the known magic bytes (4D 53 46 54 02 00 01 00) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .tlb files?

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

Is it safe to open .tlb files?

OLE (.tlb) 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.