Skip to content

Quicken QuickFinder Information File (.idx)

.idx file signature | application/octet-stream

Quicken QuickFinder Information File (IDX) is a data file format associated with Quicken personal finance software, developed and maintained by Intuit. It stores index information used to support searching and organizing account, transaction, and report data within Quicken and related legacy components. The format is primarily historical and may appear in older Quicken installations; it contains no known inherent security risk beyond the usual caution applied to untrusted files.

Safe

Magic Bytes

Offset 0
49 4E 44 58

Sources: Wikipedia

All Known Signatures

3 signature variants are documented for .idx files across multiple sources.

Hex Signature Offset Sources
49 4E 44 58 0 Wikipedia
41 4F 4C 44 42 0 Gary Kessler
50 00 00 00 20 00 00 00 0 Gary Kessler

Extension

.idx

MIME Type

application/octet-stream

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .idx files in Python

Python 
def is_idx(file_path: str) -> bool:
    """Check if file is a valid IDX by magic bytes."""
    signature = bytes([0x49, 0x4E, 0x44, 0x58])
    with open(file_path, "rb") as f:
        return f.read(4) == signature

How to validate .idx files in Node.js

Node.js 
function isIDX(buffer: Buffer): boolean {
  const signature = Buffer.from([0x49, 0x4E, 0x44, 0x58]);
  return buffer.subarray(0, 4).equals(signature);
}

How to validate .idx files in Go

Go 
func IsIDX(data []byte) bool {
    signature := []byte{0x49, 0x4E, 0x44, 0x58}
    if len(data) < 4 {
        return false
    }
    return bytes.Equal(data[:4], signature)
}

API Endpoint

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

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .idx file?

A .idx file is a Quicken QuickFinder Information File file. Quicken QuickFinder Information File (IDX) is a data file format associated with Quicken personal finance software, developed and maintained by Intuit. It stores index information used to support searching and organizing account, transaction, and report data within Quicken and related legacy components. The format is primarily historical and may appear in older Quicken installations; it contains no known inherent security risk beyond the usual caution applied to untrusted files.

What are the magic bytes for .idx files?

The magic bytes for Quicken QuickFinder Information File files are 49 4E 44 58 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .idx file?

To validate a .idx file, read the first bytes of the file and compare them against the known magic bytes (49 4E 44 58) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .idx files?

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

Is it safe to open .idx files?

Quicken QuickFinder Information File (.idx) 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.