PHP json encode - Malformed UTF-8 characters, possibly incorrectly encoded

The issue happens if there are some non-utf8 characters inside even though most of them are utf8 chars. This will remove any non-utf8 characters and now it works.

$data['name'] = mb_convert_encoding($data['name'], 'UTF-8', 'UTF-8');

If you have a multidimensional array to encode in JSON format then you can use below function:

If JSON_ERROR_UTF8 occurred :

$encoded = json_encode( utf8ize( $responseForJS ) );

Below function is used to encode Array data recursively

/* Use it for json_encode some corrupt UTF-8 chars
 * useful for = malformed utf-8 characters possibly incorrectly encoded by json_encode
 */
function utf8ize( $mixed ) {
    if (is_array($mixed)) {
        foreach ($mixed as $key => $value) {
            $mixed[$key] = utf8ize($value);
        }
    } elseif (is_string($mixed)) {
        return mb_convert_encoding($mixed, "UTF-8", "UTF-8");
    }
    return $mixed;
}

Please, make sure to initiate your Pdo object with the charset iso as utf8. This should fix this problem avoiding any re-utf8izing dance.

$pdo = new PDO("mysql:host=localhost;dbname=mybase;charset=utf8", 'user', 'password');

With php 7.2, two options allow to manage invalid UTF-8 direcly in json_encode :

https://www.php.net/manual/en/function.json-encode

json_encode($text, JSON_INVALID_UTF8_IGNORE);

Or

json_encode($text, JSON_INVALID_UTF8_SUBSTITUTE);

you just add in your pdo connection charset=utf8 like below line of pdo connection:

$pdo = new PDO("mysql:host=localhost;dbname=mybase;charset=utf8", 'user', 'password');

hope this will help you

Remove HTML entities before JSON encoding. I used html_entity_decode() in PHP and the problem was solved

$json = html_entity_decode($source);
$data = json_decode($json,true);

Do you by any chance have UUIDs in your result set? In that case the following database flag will help:

PDO::DBLIB_ATTR_STRINGIFY_UNIQUEIDENTIFIER => true

If your data is well encoded in the database for example, make sure to use the mb_ * functions for string handling, before json_encode. Functions like substr or strlen do not work well with utf8mb4 and can cut your text and leave a malformed UTF8

I know this is kind of an old topic, but for me it was what I needed. I just needed to modify the answer 'jayashan perera'.

//...code
        $stmt->execute();
        $result = $stmt->fetchAll(PDO::FETCH_ASSOC);


        for ($i=0; $i < sizeof($result) ; $i++) { 
            $tempCnpj = $result[$i]['CNPJ'];
            $tempFornecedor = json_encode(html_entity_decode($result[$i]['Nome_fornecedor']),true) ;
            $tempData = $result[$i]['efetivado_data'];
            $tempNota = $result[$i]['valor_nota'];
            $arrResposta[$i] = ["Status"=>"true", "Cnpj"=>"$tempCnpj", "Fornecedor"=>$tempFornecedor, "Data"=>"$tempData", "Nota"=>"$tempNota" ];
        }

        echo json_encode($arrResposta);

And no .js i have use

obj = JSON.parse(msg);