About WhatFileType
A file format database that respects your time and your files.
WhatFileTypeexists because looking up a file type should be quick and clean. The older sites that answer "what is a .heic file" are buried in ads and pop-ups. This one gives you the answer, above the fold, and gets out of the way.
What you get
- 289 formats with real technical detail: MIME types, magic-byte signatures, per-OS apps and conversion targets.
- An in-browser file identifierthat reads a file's signature locally. Your files never leave your device.
- A free JSON API, an embeddable widget, and a sortable magic-numbers reference.
Where the data comes from
Each record is hand-compiled from public specifications, vendor documentation and the registered MIME type lists. Magic-byte signatures are drawn from published format specs and cross-checked against two independent signature references. The full source order, what gets verified automatically on every build, and what is deliberately left out are written up on the methodology page. If you spot an error, please report it through the contact form, accuracy is the whole point.
The name
This site launched as WhatFormat and was renamed to WhatFileType in July 2026, to match the domain and to say plainly what it does. It is the same site, the same dataset and the same URLs: nothing moved. If you have a bookmark, a link or a citation under the old name, it still points here.
Privacy
The file identifier reads only the first few kilobytes of a file, in your browser, to match its signature. Nothing is uploaded, stored or logged. The rest of the site may show ads from third-party partners and use basic analytics, see the Privacy Policy for how that works and how EEA/UK consent is handled.
Who is behind it
WhatFileType is built and maintained by FusionStudios, a digital agency in the Netherlands. It is an independent reference project rather than a product: there are no accounts, no sign-ups and nothing to buy.