Hexdump
Classic offset / hex / ASCII dump of any file, like `hexdump -C`, on your device.
Hexdump prints every byte as an eight-digit hex offset, the bytes in hex, and printable ASCII between pipes. bytesPerLine takes 8, 16 or 32, default 16; bytes outside 0x20 to 0x7e show as dots. Repeated identical lines are never collapsed, so the output runs about four times the file size. A companion grid lets you click a byte to inspect it first.
Questions
Is this the same output as hexdump -C?
Close, and readable in the same way. Each line is an 8-digit hex offset, then the bytes of that line in hex separated by spaces, then the ASCII column between pipes. Bytes from 0x20 to 0x7e print as themselves and everything else prints as a dot. Unlike hexdump -C, repeated identical lines are not collapsed into a star, so every offset in the file is present in the output.
How do I change how many bytes are on each line?
With the bytesPerLine option: 8, 16 or 32, defaulting to 16. Sixteen matches the layout most write-ups and command line tools use, so offsets line up when you compare with a colleague. Thirty-two suits wide screens and spotting repeating structures; eight suits narrow records and 8-byte fields.
Can I turn the dump back into the original file?
Yes. Run From hexdump on the saved text. It strips the leading offset column and the trailing ASCII column, then reads the hex pairs that remain, so this tool's own output round-trips. The rebuilt file comes back with a .bin extension.
Is there a size limit?
No hard limit in the tool, but the whole file is held in your device's memory and the dump itself is roughly four times the file size as text. A few megabytes is fine on a laptop; a multi-gigabyte disk image is not what this is for. To look at one region of a large file, cut it out with Take bytes first, then dump the piece.
Does anything get sent anywhere?
No. The bytes are read locally and dumped in a Web Worker in this tab. Nothing is uploaded, nothing is logged and no copy of the file is kept, which is the reason this exists as a page rather than as an upload form. You can disconnect from the network and it still runs.