A commmon file extension for e-mail files (.eml)
.eml file signature | message/rfc822
EML is a de facto file format for Internet e-mail messages, based on the message/rfc822 standard defined and maintained by the IETF. It is used to store and exchange individual e-mail messages in clients such as Microsoft Outlook Express, Mozilla Thunderbird, Eudora, and similar mail programs. The format is generally safe, but messages may contain attachments, links, or scripts, so files from untrusted sources should still be handled cautiously.
Magic Bytes
Offset 0
23 21 20 72 6E 65 77 73
Sources: Apache Tika
All Known Signatures
12 signature variants are documented for .eml files across multiple sources.
| Hex Signature | Offset | Sources |
|---|---|---|
| 23 21 20 72 6E 65 77 73 | 0 | Apache Tika |
| 4E 23 21 20 72 6E 65 77 73 | 0 | Apache Tika |
| 46 6F 72 77 61 72 64 20 74 6F | 0 | Apache Tika |
| 50 69 70 65 20 74 6F | 0 | Apache Tika |
| 58 2D 4D 61 69 6C 65 72 3A | 0 | Apache Tika |
| 58 2D 4E 6F 74 65 73 2D 49 74 65 6D 3A | 0 | Apache Tika |
| 52 65 63 65 69 76 65 64 | 0 | Wikipedia |
| 46 72 6F 6D 20 20 20 | 0 | Gary Kessler |
| 46 72 6F 6D 20 3F 3F 3F | 0 | Gary Kessler |
| 46 72 6F 6D 3A 20 | 0 | Gary Kessler |
| 52 65 74 75 72 6E 2D 50 61 74 68 3A 20 | 0 | Gary Kessler |
| 58 2D | 0 | Gary Kessler |
Extension
.eml
MIME Type
message/rfc822
Byte Offset
0
Risk Level
Safe
Validation Code
How to validate .eml files in Python
def is_eml(file_path: str) -> bool:
"""Check if file is a valid EML by magic bytes."""
signature = bytes([0x23, 0x21, 0x20, 0x72, 0x6E, 0x65, 0x77, 0x73])
with open(file_path, "rb") as f:
return f.read(8) == signatureHow to validate .eml files in Node.js
function isEML(buffer: Buffer): boolean {
const signature = Buffer.from([0x23, 0x21, 0x20, 0x72, 0x6E, 0x65, 0x77, 0x73]);
return buffer.subarray(0, 8).equals(signature);
}How to validate .eml files in Go
func IsEML(data []byte) bool {
signature := []byte{0x23, 0x21, 0x20, 0x72, 0x6E, 0x65, 0x77, 0x73}
if len(data) < 8 {
return false
}
return bytes.Equal(data[:8], signature)
}API Endpoint
/api/v1/eml
curl https://filesignature.org/api/v1/eml
See the full API documentation for all endpoints and parameters.
Related Formats
Frequently Asked Questions
What is a .eml file?
A .eml file is a A commmon file extension for e-mail files file. EML is a de facto file format for Internet e-mail messages, based on the message/rfc822 standard defined and maintained by the IETF. It is used to store and exchange individual e-mail messages in clients such as Microsoft Outlook Express, Mozilla Thunderbird, Eudora, and similar mail programs. The format is generally safe, but messages may contain attachments, links, or scripts, so files from untrusted sources should still be handled cautiously.
What are the magic bytes for .eml files?
The magic bytes for A commmon file extension for e-mail files files are 23 21 20 72 6E 65 77 73 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.
How do I validate a .eml file?
To validate a .eml file, read the first bytes of the file and compare them against the known magic bytes (23 21 20 72 6E 65 77 73) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .eml files?
The primary MIME type for .eml files is message/rfc822.
Is it safe to open .eml files?
A commmon file extension for e-mail files (.eml) 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.