The text of the JSON must be encoded as UTF-8, UTF-16 or UTF-32.

The data represented by the JSON text, however, may be further encoded in other ways.

For example, in JSON, a sequence of bytes could be represented as an array of numbers, a string of hexadecimal digits, or something else. What those bytes mean to the sending and receiving applications must be agreed upon outside of JSON.

That said, the JSON specification requires that string values in JSON must be in Unicode, possibly using escape sequences. (Which are \u followed by 4 hexadecimal digits. for example, "\u005C" is a \)