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NII (.nii)

.nii file signature | application/octet-stream

Single fileNIfTIformat, used extensively in biomedical imaging.

Safe

Magic Bytes

Offset 344
6E 2B 31 00

Sources: Wikipedia

Extension

.nii

MIME Type

application/octet-stream

Byte Offset

344

Risk Level

Safe

Validation Code

How to validate .nii files in Python

Python
def is_nii(file_path: str) -> bool:
    """Check if file is a valid NII by magic bytes."""
    signature = bytes([0x6E, 0x2B, 0x31, 0x00])
    with open(file_path, "rb") as f:
        return f.read(4) == signature

How to validate .nii files in Node.js

Node.js
function isNII(buffer: Buffer): boolean {
  const signature = Buffer.from([0x6E, 0x2B, 0x31, 0x00]);
  return buffer.subarray(0, 4).equals(signature);
}

How to validate .nii files in Go

Go
func IsNII(data []byte) bool {
    signature := []byte{0x6E, 0x2B, 0x31, 0x00}
    if len(data) < 4 {
        return false
    }
    return bytes.Equal(data[:4], signature)
}

API Endpoint

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

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .nii file?

A .nii file is a NII file. Single fileNIfTIformat, used extensively in biomedical imaging.

What are the magic bytes for .nii files?

The magic bytes for NII files are 6E 2B 31 00 at byte offset 344. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .nii file?

To validate a .nii file, read the first bytes of the file and compare them against the known magic bytes (6E 2B 31 00) at offset 344. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .nii files?

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

Is it safe to open .nii files?

NII (.nii) 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.