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⌁ DEVELOPER UTILITY · PIXELOKAY STUDIO

File Signature Inspector

Reveal a file's likely format using its magic bytes — not the extension somebody gave it. Compare evidence, investigate mismatches and generate clean inspection reports.

◆ Signature-first detection⌁ Hex evidence◎ Private, on-device
YOUR WORKSPACE

Inspect files

Files never leave this browser
Files analyzed0Completed inspections
Identified0Recognized signatures
Differences0Extension mismatches
Unknown0No recognized match

Inspection results

Add files to begin your analysis.

No files inspected yet

Drop in a file to see its signature, likely type, extension status and raw bytes.

Browse supported file signatures

Reference signatures are identification clues, not evidence that a file is structurally valid. Container subtypes need additional internal evidence.

UNDERSTAND YOUR FILES

What are file signatures?

A file signature (or “magic number”) is a recognizable sequence of bytes, often near the beginning of a file. For example, PNG images begin with 89 50 4E 47 0D 0A 1A 0A, even if someone renames the file to end in .jpg.

01

Select files

Use the picker or drag files into the workspace. Only bounded portions are read by the browser; the tool does not upload them.

02

Check the evidence

Compare the detected format against its extension and view the exact bytes or container clues that led to the result.

03

Share a report

Export results as JSON or CSV for records, inventory audits, development or troubleshooting.

Frequently asked questions

Can a file extension be misleading?

Yes. Extensions are filename labels and can be renamed without changing file content. A signature-based inspection can reveal some mismatches.

Does a matching magic byte mean the file is safe?

No. A header can be copied or forged; this tool cannot verify full file integrity, detect malware or establish trustworthiness.

Why is my TXT, JSON or CSV file unknown?

Many text formats do not have unique required byte signatures. This tool intentionally avoids claiming a format based only on an extension or a loose text heuristic.

Can this distinguish ZIP, DOCX, XLSX, PPTX and EPUB?

When the ZIP central directory is readable within inspection limits, the tool can inspect entry names and certain small, stored metadata without extracting the archive. Some unusual ZIP files remain classified simply as ZIP.

Are very large files uploaded or loaded fully into memory?

No. Files remain on your device, and the analyzer reads small slices from the beginning, end and, when necessary, a bounded ZIP directory. Hex viewing reads only the requested slice.

Using File Signature Inspector

Compare local file bytes with known signature and container clues, review offsets and hex evidence, and export a cautious format assessment.

Workflow

  1. Choose local files for inspection
  2. review likely signature matches alongside extension and MIME context
  3. inspect bounded header, tail, offset or ZIP clues, then export per-file JSON or batch CSV/JSON.

Example

Inspect a file whose extension differs from its likely signature, compare the byte evidence and container clues, then export a JSON report that records uncertainty.

Limits and data handling

The 60 signature families and container clues indicate likely formats, not complete structural validity, safety or provenance. Extension and MIME are context only. ZIP directory inspection is bounded, and ambiguous macro subtypes may remain unverified. No payload is executed. Hex evidence and filenames can be sensitive; review reports before sharing.

FAQs

Does a detected signature prove the entire file is valid?

No. Signature bytes are clues and do not validate every structure or payload.

Does this tool check whether a file is malicious?

No. It inspects format evidence and does not replace malware scanning.

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