Random string generator is a tool which could help to generate random string based on your chosen characters. By default is generating a 16 character string length.
The output contains characters from allowed characters field, which is by default using all upper and lower case 26 letters a-z respectively A-Z and numbers 0-9 (alpha-numeric string). You can specify allowed characters set in more input options and also how many string you would like to generate by field number of strings, where the default value is 1.
Although this tool has no pattern for random generation, if you look for random secure string, use secure string generator listed in related tools below.