Fuzzy bitmap magic bytes (.fbm)
.fbm file signature: 25 62 69 74 6D 61 70 | application/octet-stream
Category: Images
Fuzzy bitmap (FBM) is a raster image file format originally developed for the Fuzzy Bitmap image utility and preserved by image-processing software. It is used to store bitmap graphics for viewing, conversion, and archival in older Unix-based workflows and related graphics tools. The format is largely historical, and files are generally safe to open, though unsupported readers may not handle them reliably.
Magic Bytes
Offset 0
25 62 69 74 6D 61 70
Sources: Gary Kessler
Validation Code
How to validate .fbm files in Python
def is_fbm(file_path: str) -> bool:
"""Check if file is a valid FBM by magic bytes."""
signature = bytes([0x25, 0x62, 0x69, 0x74, 0x6D, 0x61, 0x70])
with open(file_path, "rb") as f:
return f.read(7) == signatureHow to validate .fbm files in Node.js
function isFBM(buffer: Buffer): boolean {
const signature = Buffer.from([0x25, 0x62, 0x69, 0x74, 0x6D, 0x61, 0x70]);
return buffer.subarray(0, 7).equals(signature);
}How to validate .fbm files in Go
func IsFBM(data []byte) bool {
signature := []byte{0x25, 0x62, 0x69, 0x74, 0x6D, 0x61, 0x70}
if len(data) < 7 {
return false
}
return bytes.Equal(data[:7], signature)
}API Endpoint
/api/v1/fbm
curl https://filesignature.org/api/v1/fbm
See the full API documentation for all endpoints and parameters.
Related Formats
Frequently Asked Questions
What is a .fbm file?
A .fbm file is a Fuzzy bitmap file. Fuzzy bitmap (FBM) is a raster image file format originally developed for the Fuzzy Bitmap image utility and preserved by image-processing software. It is used to store bitmap graphics for viewing, conversion, and archival in older Unix-based workflows and related graphics tools. The format is largely historical, and files are generally safe to open, though unsupported readers may not handle them reliably.
What are the magic bytes for .fbm files?
The magic bytes for Fuzzy bitmap (.fbm) files are 25 62 69 74 6D 61 70 at byte offset 0. These bytes identify the file format more reliably than the extension alone.
How do I validate a .fbm file?
To validate a .fbm file, read the first bytes of the file and compare them against the known magic bytes (25 62 69 74 6D 61 70) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .fbm files?
There is no officially registered MIME type for .fbm files. Systems typically use application/octet-stream as a generic fallback when handling this format.
Is it safe to open .fbm files?
Fuzzy bitmap (.fbm) 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.