UTF-8

The standard way to store text as bytes: plain English letters take one byte each, other characters take two to four.

UTF-8 encodes every Unicode character as 1-4 bytes, with ASCII characters unchanged as single bytes; it is the default text encoding of JSON, MQTT strings and HTTP.

Examples

21.5 °C is 7 characters but 8 bytes in UTF-8, because the degree sign takes two bytes.
A plain ASCII name like bench1 is already valid UTF-8, one byte per letter.