File Signature Checker

A focused three-step workflow

How to use the file signature checker

1
Add only what the tool needs
Enter the relevant values, paste the source or select a local file. Input remains in this browser tab.
2
Use the advanced controls
Adjust matching, timing, measurement or inspection options. Safe defaults are selected for the most common task.
3
Review result and evidence
Use the diagnostics, warnings and supporting measurements to verify the main result before acting on it.

More than a one-number result

Verify whether a file’s real byte signature matches its name and browser-reported type. Review mismatches before opening suspicious downloads. The workspace keeps the primary action quick while exposing the evidence that basic alternatives often omit.

Magic-byte detection for common formatsIncluded in the same responsive workspace with clear labels and practical output.

Extension and MIME comparisonIncluded in the same responsive workspace with clear labels and practical output.

Polyglot-risk hintsIncluded in the same responsive workspace with clear labels and practical output.

Only the first bytes are inspected locallyIncluded in the same responsive workspace with clear labels and practical output.

Private browser processing

Rantey performs this task with browser capabilities on your device. Selected files and entered data are not posted to an application endpoint. For sensitive work, still review the result and follow your organization’s security policy.

Mobile-ready and accessible

Controls stack on narrow screens, buttons keep large touch targets and wide diagnostic tables scroll inside their own container. Keyboard focus, status messages and readable contrast are included for desktop and mobile use.

Frequently asked questions