FILE TOOL // 012

File Type Authenticity Checker

Check whether a file's extension agrees with its browser MIME label and recognizable header bytes.

Processed locally in your browser

File Type Authenticity Checker

Local browser processing
FileSizeType
No files selected.
Choose files to begin.0 files
Advertisement

How to use File Type Authenticity Checker

  1. Add the requested files.
  2. Review the options and the displayed queue.
  3. Select Check File Types, inspect the result, and download the generated Generated file.

What this file tool does

This checker reads real file headers and reports extension, browser MIME, detected signature, and whether those signals agree.

Read a small byte prefix, identify known signatures, then compare independent type signals.

Magic-byte recognition is a format check, not antivirus scanning, and unknown or container formats can require specialist analysis.

Supported inputs and limits

The tool works with files exposed through the browser picker. Actual limits depend on available device memory and browser support.

ItemSupport
InputFiles selected in the browser
OutputGenerated file
ProcessingLocal browser session

Example and practical tips

Practical example

A file named invoice.pdf whose bytes begin with an executable header is clearly flagged for review.

Tips

  • Keep an untouched copy of important source files.
  • Review the result list before using the download.
  • For large batches, test a small sample first.

Frequently asked questions

How can I tell if a file extension is fake?

Compare the extension with recognizable header bytes; this tool reports disagreements directly.

Does a matching file signature prove a file is safe?

No. It only supports format identification and does not scan for malware.

Which file signatures can this checker recognize?

It recognizes common PDF, ZIP, PNG, JPEG, GIF, WebP, GZIP, RAR, 7z, ELF, PE, and media signatures.

Why does my file show as unknown?

Some formats have no fixed signature, use a container, or need deeper parsing than a browser-side header check.

Are files uploaded for type detection?

No. The selected byte prefixes are read locally in your browser.

At a glance

ItemSupport
InputFiles selected in the browser
OutputGenerated file
ProcessingLocal browser session

Browse more file tools

Callfile categories
File Organization & Naming

Rename, clean, sequence, and validate file names.

View all
Archive & Compression

Create, inspect, compress, and extract archives.

View all
Integrity & Verification

Generate checksums, manifests, and signatures.

View all
File Inspection & Analysis

Inspect bytes, headers, MIME types, and entropy.

View all
Folder & Storage Analysis

Analyze folder size, contents, age, and distribution.

View all
File Splitting & Assembly

Split, join, extract, patch, and verify chunks.

View all
File Security & Privacy

Encrypt files and inspect privacy or safety signals.

View all
Backup & Change Tracking

Compare backup sets and detect file changes.

View all