php curl send post data in json code example

Example 1: curl post json

curl -X POST -H "Content-Type: application/json" \
 -d '{"username":"abc","password":"abc"}' \
 https://api.example.com/v2/login

Example 2: curl pass raw json in post request

If you wanna use Content-type: application/json and raw data, seem your data 
should be in json format

$ch = curl_init();
$headers  = [
            'x-api-key: XXXXXX',
            'Content-Type: text/plain'
        ];
$postData = [
    'data1' => 'value1',
    'data2' => 'value2'
];
curl_setopt($ch, CURLOPT_URL,"XXXXXX");
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($postData));           
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
$result     = curl_exec ($ch);
$statusCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);