PHP check if a string is JSON

Simple method will be:

if( is_array(json_decode($string,true)) ){
    echo true;
}
else{
    echo false;
}

This method doesn’t rely on heuristics, uses native php functionality, and is about as future-proof as you’re gonna get; it just tells you straight up whether there were any errors in decoding the string.

function isJson($string) {
 json_decode($string);
 return (json_last_error() == JSON_ERROR_NONE);
}

By Keenlio, April 7, 2014