WASM (.wasm)

.wasm file signature | application/wasm

WebAssemblybinary format[67]

Safe

Magic Bytes

Offset 0


              00 61 73 6D

Sources: Wikipedia

Extension

.wasm

MIME Type

application/wasm

Byte Offset

Risk Level

Safe

Validation Code

How to validate .wasm files in Python

Python

def is_wasm(file_path: str) -> bool:
    """Check if file is a valid WASM by magic bytes."""
    signature = bytes([0x00, 0x61, 0x73, 0x6D])
    with open(file_path, "rb") as f:
        return f.read(4) == signature

How to validate .wasm files in Node.js

Node.js

function isWASM(buffer: Buffer): boolean {
  const signature = Buffer.from([0x00, 0x61, 0x73, 0x6D]);
  return buffer.subarray(0, 4).equals(signature);
}

How to validate .wasm files in Go

func IsWASM(data []byte) bool {
    signature := []byte{0x00, 0x61, 0x73, 0x6D}
    if len(data) < 4 {
        return false
    }
    return bytes.Equal(data[:4], signature)
}

API Endpoint

GET /api/v1/wasm


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

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .wasm file?

A .wasm file is a WASM file. WebAssemblybinary format[67]

What are the magic bytes for .wasm files?

The magic bytes for WASM files are 00 61 73 6D at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .wasm file?

To validate a .wasm file, read the first bytes of the file and compare them against the known magic bytes (00 61 73 6D) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .wasm files?

The primary MIME type for .wasm files is application/wasm.

Is it safe to open .wasm files?

WASM (.wasm) 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.