File Type Detector: Identify Files by Magic Bytes
The File Type Detector identifies a file by checking its opening bytes against more than 30 magic-number signatures, including common image, archive, audio, video, executable, and database formats. You can provide a file or paste a hexadecimal string. If no signature matches, it checks content for JSON or XML, and displays the first 64 bytes as a hex dump for inspection.
The File Type Detector identifies file formats by examining their opening bytes, often called magic bytes. Provide a file or paste a hexadecimal string, and the tool compares the data with a library of more than 30 magic-number signatures. It recognizes formats including PNG, JPEG, GIF, WebP, PDF, ZIP, GZIP, 7z, RAR, MP3, MP4, WAV, ELF, PE, Mach-O, SQLite, and WebAssembly.
When none of the signatures fits, the detector falls back to a content heuristic for JSON and XML. It also displays the first 64 bytes as a hex dump, giving you a direct view of the data that was checked. This helps when you want to inspect the bytes behind a result rather than relying only on a filename or extension.
File formats use different structures to represent information. Many binary formats include recognizable signatures near the beginning of a file, while JSON and XML are text formats that can be identified through their content. Checking the bytes can help you investigate an unknown file or confirm its format when its name is not informative.
The File Type Detector runs entirely in your browser: your input is processed on your device and is not uploaded, stored, or sent to a server. It is free to use, and after the page loads it works offline because it has no server dependency. Developers and DevOps engineers can use it for quick file checks, while anyone inspecting unfamiliar data can review the detected type and its opening bytes.
Step 1: Provide a file or paste a hexadecimal string. The detector uses the file’s opening bytes or the bytes represented by your hex input.
Step 2: Review and adjust any available options. The tool checks the input against its magic-number signatures and content heuristics.
Step 3: Review the detected file type. If no signature matches, the detector checks the content for JSON or XML.
Step 4: Inspect the hex dump and copy the result. The dump shows the first 64 bytes so you can see the data the detector examined.
Use case: Identify an unfamiliar file during a routine debugging task without installing a local utility.
Use case: Check a file from whichever machine you are using by running the detector in your browser.
Use case: Inspect sensitive or internal files without pasting their contents into a third-party service; processing stays in your browser.
Use case: Investigate a file whose extension does not make its actual format clear by checking its magic bytes.
Use case: Triage an unknown binary file by comparing its opening bytes with signatures for formats such as ZIP, PDF, or SQLite.
Use case: Review the first 64 bytes as a hex dump when you need to understand which bytes were checked for a format match.