File Type Detector & Hex Viewer
Find out what a file really is. The tool reads the file signature, the first bytes that identify its true format, instead of trusting the extension, and shows you the raw bytes in a hex view.
A file type detector tells you what a file really is by reading its signature, the first bytes that identify the true format, rather than trusting the extension. Drop in a file with a missing, wrong or unknown extension and see its real type, MIME type and matching extension, plus a hex view of the raw bytes, so it works to identify an unknown file or check a file's magic number. A signature that disagrees with the extension is also a useful warning sign. Everything runs in your browser.
Read the guide: How to Identify an Unknown File TypeDrop a file here, or click to browse
Inspected entirely in your browser — nothing is uploaded.
How it works
- 1
Drop any file
Add a file with a missing, wrong or unknown extension.
- 2
See its true type
The real format is identified from the file signature, with the matching MIME type and extension.
- 3
Inspect the bytes
Scroll the hex viewer to read the raw contents alongside the decoded text.
Instant & 100% private — nothing is uploaded
Everything runs locally in your browser. Your files are processed on your own device and are never sent to a server, so there are no upload waits, no size limits from us, and nothing is ever stored or logged.
Frequently asked questions
- How can it tell the type without a file extension?
- Most formats begin with a known signature, a fixed sequence of bytes sometimes called a magic number. The tool matches those bytes against a catalogue of formats, so a renamed or extension-less file is still identified correctly.
- Why does the detected type differ from the extension?
- Extensions can be wrong or deliberately changed. When the signature and extension disagree, the signature is the reliable answer. That mismatch is also a useful warning sign for a suspicious file.
- What is the hex viewer for?
- It shows the raw bytes of the file as hexadecimal next to their text characters, which is handy for spotting headers, embedded strings or corruption.
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