Hex to ASCII and ASCII to Hex

Yes. In the hex-to-text direction all whitespace is ignored and an optional 0x or 0X in front of each byte is stripped, so '0x48 0x65' decodes to 'He'. This lets you paste hex copied from a debugger, hex dump or code listing without cleaning it up first.

Each byte is exactly two hex digits, so the input must have an even number of digits after spaces and 0x prefixes are removed. An odd count means one byte is missing a digit, so the tool stops and asks you to add it rather than guessing.

Decoding only accepts the digits 0 to 9 and letters A to F in either case. Any other character, such as a stray g or a punctuation mark, triggers a 'contains a non-hex character' error so you do not get silently wrong output.

Yes. Text is encoded and decoded as UTF-8, so accented letters, symbols and emoji round-trip correctly. A character like é becomes two bytes (c3 a9), and a snowman becomes three bytes (e2 98 83), which is why the hex is longer than the visible text.

Yes, in the text-to-hex direction. You can output uppercase digits and set any separator string between bytes, for example a space to get '48 69' instead of '4869'. Those two options only appear when you switch to 'Text to hex'.

For the classic English letters, digits and punctuation that fit in one byte, ASCII and UTF-8 are identical, so plain text behaves exactly as you expect. UTF-8 is a strict superset, so anything beyond ASCII just uses more bytes; nothing is lost.

An empty input produces an empty result with no error. This makes it safe to clear the box and start over, and it means whitespace-only hex input also decodes to nothing.

Yes. Everything runs locally in your browser and nothing is uploaded, so you can safely convert tokens, keys or other sensitive strings. The page also works offline once loaded.

Yes. A JSON endpoint accepts a 'text' field and a 'mode' of 'hex-to-text' or 'text-to-hex', plus optional 'separator' and 'uppercase' for the encode direction, and returns the converted string.