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AOL history (.arl)

.arl file signature | application/octet-stream

AOL History (ARL) is a legacy file format used by America Online (AOL) to store records of browsing or navigation activity within its software. It was primarily used to track visited web addresses and related history data in AOL client applications, including companion typed-URL records. The format is generally safe and of historical interest only, as it is associated with older AOL software and is rarely encountered in modern systems.

Safe

Magic Bytes

Offset 0
D4 2A

Sources: Gary Kessler

Extension

.arl

MIME Type

application/octet-stream

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .arl files in Python

Python 
def is_arl(file_path: str) -> bool:
    """Check if file is a valid ARL by magic bytes."""
    signature = bytes([0xD4, 0x2A])
    with open(file_path, "rb") as f:
        return f.read(2) == signature

How to validate .arl files in Node.js

Node.js 
function isARL(buffer: Buffer): boolean {
  const signature = Buffer.from([0xD4, 0x2A]);
  return buffer.subarray(0, 2).equals(signature);
}

How to validate .arl files in Go

Go 
func IsARL(data []byte) bool {
    signature := []byte{0xD4, 0x2A}
    if len(data) < 2 {
        return false
    }
    return bytes.Equal(data[:2], signature)
}

API Endpoint

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

See the full API documentation for all endpoints and parameters.

Related Formats

.aut

Frequently Asked Questions

What is a .arl file?

A .arl file is a AOL history file. AOL History (ARL) is a legacy file format used by America Online (AOL) to store records of browsing or navigation activity within its software. It was primarily used to track visited web addresses and related history data in AOL client applications, including companion typed-URL records. The format is generally safe and of historical interest only, as it is associated with older AOL software and is rarely encountered in modern systems.

What are the magic bytes for .arl files?

The magic bytes for AOL history files are D4 2A at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .arl file?

To validate a .arl file, read the first bytes of the file and compare them against the known magic bytes (D4 2A) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .arl files?

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

Is it safe to open .arl files?

AOL history (.arl) 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.