Hex viewer
Inspect a file in hex and ASCII, type detected from magic bytes.
- Instant
- Free
- Private (processed locally)
- No sign-up
See a file as it really is
The extension sometimes lies; the bytes never do. This viewer shows the raw content in hexadecimal and ASCII and recognises the real format from its start signature — all without sending anything online.
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Choose a file
Or use the PNG sample loaded by default.
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Read the dump
Offset, bytes in hex, and an aligned ASCII column.
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Check the type
The magic bytes reveal the true format.
Common file signatures
| Format | Magic bytes (hex) | ASCII |
|---|---|---|
| PNG | 89 50 4E 47 | .PNG |
| JPEG | FF D8 FF | — |
| 25 50 44 46 | ||
| ZIP / Office | 50 4B 03 04 | PK.. |
| GIF | 47 49 46 38 | GIF8 |
Everything is read locally via FileReader: no byte leaves your browser.
Frequently asked questions
What are magic bytes?
They are the first bytes of a file, forming a signature that identifies its format. A PNG starts with “89 50 4E 47”, a PDF with “25 50 44 46” (%PDF). They are more reliable than the extension, which can be faked.
How do I read a hex dump?
Each line shows the offset (position in the file in hex), 16 bytes in hexadecimal, then their ASCII equivalent. Non-printable bytes are replaced with a dot “.”. This is the classic hex-editor view.
Is the file sent anywhere?
No. Reading happens entirely in your browser via the FileReader API. No byte is transmitted to a server, which makes the tool safe even for sensitive files.
Why are only the first bytes shown?
To stay fast and lightweight, the tool shows only an excerpt from the start (a few kilobytes). That is more than enough to identify the type and inspect the header, where magic bytes and metadata live.