Good uses
- Check whether a downloaded file's byte signature agrees with its extension and browser-reported MIME type.
- Inspect a file that an upload portal rejected as the wrong format before renaming or converting it.
Archives And File Inspection
File type checker
Check a file's real type from its byte signature, MIME type, and extension. The file stays in your browser.
Runs in your browser ยท Files stay on your device
Waiting
Runs in your browser. Files do not leave your device.
Input
File type checker. Inspect file type from local bytes.
Drop fileUp to 25MB. Local only.DropBrowsePaste
Tool notes
Before you share
Result What you get
Check a file's signature and reported type before opening it.
Input
any
Output
file-report
Steps Run order and common questions
- Choose or enter any in the workbench.
- Run the inspection tool locally in your browser.
- Review the file-report result, then copy or download it if the workbench offers that action.
- Use related retained tools for validation, cleanup, conversion, or the next workflow step.
Use it well Examples, checks, limits, and recovery paths
Bad inputs
- Files that need malware analysis rather than format identification.
- Very short, encrypted, or proprietary files without a recognizable signature.
- Assuming a matching extension proves that the contents are trustworthy.
Output checklist
- Compare the detected signature, filename extension, and browser MIME type.
- Treat disagreements as a reason to inspect the source before opening or uploading it.
- Use the reported byte signature as identification evidence, not a safety verdict.
Failure modes
- Some text-based and proprietary formats have no stable magic-byte signature.
- Container formats can share signatures even when their internal document types differ.
- A renamed file can still produce an unknown result when its leading bytes are incomplete or damaged.
Runtime limits
- Runs locally and reads only the selected file in the current browser tab.
- Identification is based on known signatures, extension, MIME type, and available browser metadata.
- The report does not upload, open, execute, or scan the file for malware.