Guides
In-depth, vendor-neutral guides on file signatures, magic bytes, and how to detect or validate file types by their content rather than their extension.
Secure File Upload Validation
Build safer file upload validation with magic byte checks, allowlists, container inspection, safe storage, and server-side processing controls.
Magic Bytes vs MIME Type vs File Extension
Compare magic bytes, MIME types, and file extensions so upload validation and file detection use the right signal for the right job.
How to Identify a File Without an Extension
Identify an unknown file without trusting its extension by reading header bytes, checking offsets, and comparing magic bytes against known signatures.
Validate File Types by Magic Bytes
Validate a file's real type by its magic bytes, not its extension. Server-side code in Python, Node.js, and Go, plus offsets and container collisions.