EPSI
application/postscript
Magic Bytes
Offset: 0
25 21
Encapsulated PostScript Interchange (EPSI) is a legacy vector graphics format developed by Adobe Systems as a specialized subset of the Encapsulated PostScript standard. It was primarily used to embed platform-independent ASCII bitmap previews within documents, facilitating visual representation on systems that lacked native PostScript rendering engines. Although now largely obsolete in modern publishing workflows, the format remains technically safe for use as it typically contains only static graphical instructions and preview data.
Validation Code
How to validate .epsi files in Python
Python
def is_epsi(file_path: str) -> bool:
"""Check if file is a valid EPSI by magic bytes."""
signature = bytes([0x25, 0x21])
with open(file_path, "rb") as f:
return f.read(2) == signatureHow to validate .epsi files in Node.js
Node.js
function isEPSI(buffer: Buffer): boolean {
const signature = Buffer.from([0x25, 0x21]);
return buffer.subarray(0, 2).equals(signature);
}
Go
func IsEPSI(data []byte) bool {
signature := []byte{0x25, 0x21}
if len(data) < 2 {
return false
}
return bytes.Equal(data[:2], signature)
}API Endpoint
GET
/api/v1/epsi
curl https://filesignature.org/api/v1/epsi