Identify any file type

Drop a mystery file. Its first bytes are compared with a library of known signatures to tell you what it really is — then it opens.

Drag & drop any file here

or click to choose — you can also paste with Ctrl+V

Choose file

Detects the real format · never uploaded · works offline

How it works

Almost every format starts with a fixed byte pattern, the "magic number": PDF files start with %PDF, ZIP with PK, PNG with \x89PNG. The name can lie; the bytes rarely do.

When you need it

Email attachments that lost their extension, downloads saved as .bin or .dat, files renamed by mistake, or a .pdf that is really a Word document.