SRT (.srt)

.srt file signature | application/x-subrip

Safe

Magic Bytes

Offset 0


              31 0A 30 30

Sources: Apache Tika

All Known Signatures

6 signature variants are documented for .srt files across multiple sources.

Hex Signature	Offset	Sources
31 0A 30 30	0	Apache Tika
31 0D 30 30	0	Apache Tika
30 78 33 31 30 44 30 41 31 33 30 33 30	0	Apache Tika
EF BB BF 31 0A 30 30	0	Apache Tika
EF BB BF 31 0D 30 30	0	Apache Tika
30 78 45 46 42 42 42 46 33 31 30 44 30 41 31 33 30 33 30	0	Apache Tika

Extension

.srt

MIME Type

application/x-subrip

Byte Offset

Risk Level

Safe

Validation Code

How to validate .srt files in Python

Python

def is_srt(file_path: str) -> bool:
    """Check if file is a valid SRT by magic bytes."""
    signature = bytes([0x31, 0x0A, 0x30, 0x30])
    with open(file_path, "rb") as f:
        return f.read(4) == signature

How to validate .srt files in Node.js

Node.js

function isSRT(buffer: Buffer): boolean {
  const signature = Buffer.from([0x31, 0x0A, 0x30, 0x30]);
  return buffer.subarray(0, 4).equals(signature);
}

How to validate .srt files in Go

func IsSRT(data []byte) bool {
    signature := []byte{0x31, 0x0A, 0x30, 0x30}
    if len(data) < 4 {
        return false
    }
    return bytes.Equal(data[:4], signature)
}

API Endpoint

GET /api/v1/srt


              curl https://filesignature.org/api/v1/srt

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .srt file?

A .srt file is a SRT file.

What are the magic bytes for .srt files?

The magic bytes for SRT files are 31 0A 30 30 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .srt file?

To validate a .srt file, read the first bytes of the file and compare them against the known magic bytes (31 0A 30 30) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .srt files?

The primary MIME type for .srt files is application/x-subrip.

Is it safe to open .srt files?

SRT (.srt) 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.