MIME Type Inspector

Paste a Base64 string to detect its true MIME type and file format.

Last Updated: August 2026
100% Client-Side — Your data never leaves your device

Why this tool is safe

Your data never leaves your device — everything runs in your browser.

No server uploads. Other tools send your files to their servers. Ours don't.
Zero tracking of content. We never see, store, or log anything you convert.
Works offline. Once loaded, the tool works without an internet connection.
No account required. Instantly use all tools completely free without signing up.

Frequently Asked Questions

Search below or browse through our most commonly asked questions.

Files have unique starting bytes (called 'magic numbers') that identify their format. For example, PNG images always start with '89 50 4E 47'. This tool decodes the first few bytes of your Base64 string and matches them against known signatures.

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