The [json_encode](<http://php.net/manual/en/function.json-encode.php>) function will convert a PHP array (or, since PHP 5.4, an object which implements the JsonSerializable interface) to a JSON-encoded string. It returns a JSON-encoded string on success or FALSE on failure.

$array = [
    'name' => 'Jeff',
    'age' => 20,
    'active' => true,
    'colors' => ['red', 'blue'],
    'values' => [0=>'foo', 3=>'bar'],
];

During encoding, the PHP data types string, integer, and boolean are converted to their JSON equivalent. Associative arrays are encoded as JSON objects, and – when called with default arguments – indexed arrays are encoded as JSON arrays. (Unless the array keys are not a continuous numeric sequence starting from 0, in which case the array will be encoded as a JSON object.)

echo json_encode($array);

Output:

{"name":"Jeff","age":20,"active":true,"colors":["red","blue"],"values":{"0":"foo","3":"bar"}}

Arguments

Since PHP 5.3, the second argument to json_encode is a bitmask which can be one or more of the following.

As with any bitmask, they can be combined with the binary OR operator |.

[JSON_FORCE_OBJECT](<http://php.net/manual/en/json.constants.php#constant.json-force-object>)

Forces the creation of an object instead of an array

$array = ['Joel', 23, true, ['red', 'blue']];
echo json_encode($array);
echo json_encode($array, JSON_FORCE_OBJECT);

Output:

["Joel",23,true,["red","blue"]]
{"0":"Joel","1":23,"2":true,"3":{"0":"red","1":"blue"}}

[JSON_HEX_TAG](<http://php.net/manual/en/json.constants.php#constant.json-hex-tag>), [JSON_HEX_AMP](<http://php.net/manual/en/json.constants.php#constant.json-hex-amp>), [JSON_HEX_APOS](<http://php.net/manual/en/json.constants.php#constant.json-hex-apos>), [JSON_HEX_QUOT](<http://php.net/manual/en/json.constants.php#constant.json-hex-quot>)

Ensures the following conversions during encoding:

Constant | Input | Output | —| — | — |

|JSON_HEX_TAG | \\< | \\u003C | |JSON_HEX_TAG | \\> | \\u003E | |JSON_HEX_AMP | & | \\u0026 | |JSON_HEX_APOS | \\' | \\u0027 | |JSON_HEX_QUOT | " | \\u0022 |

$array = ["tag"=>"<>", "amp"=>"&", "apos"=>"'", "quot"=>"\\""];
echo json_encode($array);
echo json_encode($array, JSON_HEX_TAG | JSON_HEX_AMP | JSON_HEX_APOS | JSON_HEX_QUOT);