MIME Type & File Signature Lookup

45 common file formats with their MIME type, magic bytes (the file signature at the start of the file that identifies its real format, regardless of extension), typical applications, and OS. Search by extension, MIME type, a magic-byte hex fragment, or a keyword. This is a reference only — it doesn't inspect or upload actual files. Runs entirely in your browser; nothing you search is sent anywhere.

A note on scope

Some formats share identical magic bytes — .docx/.xlsx/.pptx are all ZIP archives underneath, and legacy .doc/.xls/.ppt/.msi all share the same OLE Compound File Binary header — so a magic-byte search for those returns every format that uses it; the extension alone doesn't disambiguate without inspecting the archive/stream contents. Plain-text formats (JSON, YAML, CSV, TXT) have no reliable magic bytes at all. This is a reference only — it doesn't upload, open, or execute files.