I found no solution for this.
I have an API witch give me JSON resposne,
http://api.vajehyab.com/v2/public/?q=%D8%B3%D9%84%D8%A7%D9%85&developer=stackoverflow
which is something like this,
{"search":{"q":"\u0633\u0644\u0627\u0645","code":200},"data":{"title":"\u0633\u0644\u0627\u0645","pronunciation":"","text":"(\u0633\u064e) [ \u0639 . ] (\u0645\u0635 \u0644 .) 1 - \u062f\u0631\u0648\u062f \u06af\u0641\u062a\u0646 . 2 - \u0628\u06cc \u06af\u0632\u0646\u062f \u0634\u062f\u0646 . 3 - \u06af\u0631\u062f\u0646 \u0646\u0647\u0627\u062f\u0646 . \u061b ~ \u0639\u0644\u06cc\u06a9 \u062f\u0631\u0648\u062f \u0628\u0631 \u062a\u0648 \u0628\u0627\u062f. \u061b ~ \u0639\u0644\u06cc\u06a9\u0645 \u062f\u0631\u0648\u062f \u0628\u0631 \u0634\u0645\u0627. ","source":"\u0641\u0631\u0647\u0646\u06af \u0641\u0627\u0631\u0633\u06cc \u0645\u0639\u06cc\u0646 | \u0648\u0627\u0698\u0647 \u06cc\u0627\u0628","permalink":"?q=%D8%B3%D9%84%D8%A7%D9%85"},"error":{"message":"","reason":""},"ads":{"text":"","url":""}}
It doesn't seem to have problem ,I can decode it in other tools but PHP, I can't decode it in PHP
$json = file_get_contents('http://api.vajehyab.com/v2/public/?q='.urlencode('سلام').'&developer=stackoverflow');
var_dump(json_decode($json)); // null
I hope somebody could help me with this, thank you...