(PHP 8 >= 8.3.0)
json_validate — Checks if a string contains valid JSON
   Returns whether the given string is syntactically valid JSON.
   If json_validate() returns true, json_decode()
   will successfully decode the given string when using the same
   depth and flags.
  
   If json_validate() returns false, the cause
   can be retrieved using json_last_error() and
   json_last_error_msg().
  
json_validate() uses less memory than json_decode() if the decoded JSON payload is not used, because it does not need to build the array or object structure containing the payload.
Calling json_validate() immediately before json_decode() will unnecessarily parse the string twice, as json_decode() implicitly performs validation during decoding.
json_validate() should therefore only be used if the decode JSON payload is not immediately used and knowing whether the string contains valid JSON is needed.
jsonThe string to validate.
This function only works with UTF-8 encoded strings.
Note:
PHP implements a superset of JSON as specified in the original » RFC 7159.
depth
       Maximum nesting depth of the structure being decoded.
       The value must be greater than 0,
       and less than or equal to 2147483647.
      
flags
       Currently only
       JSON_INVALID_UTF8_IGNORE
       is accepted.
      
   Returns true if the given string is syntactically valid JSON, otherwise
   returns false.
  
   If depth is outside the allowed range,
   a ValueError is thrown.
  
   If flags is not a valid flag,
   a ValueError is thrown.
  
Example #1 json_validate() examples
<?php
var_dump(json_validate('{ "test": { "foo": "bar" } }'));
var_dump(json_validate('{ "": "": "" } }'));
?>The above example will output:
bool(true) bool(false)