wapim-text.php

<?php

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, 'https://api.wapim.io/api/v1/whatsapp/message/text');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, "{\"phone_number\": \"RECIPIENT_NUMBER\", \"message\" : \"Hello Wapim\"}");

$headers = array();
$headers[] = 'Token: YOUR_WAPIM_TOKEN';
$headers[] = 'Content-Type: application/x-www-form-urlencoded';
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

$result = curl_exec($ch);
if (curl_errno($ch)) {
    echo 'Error:' . curl_error($ch);
}
curl_close($ch);

$result = curl_exec($ch);
if (curl_errno($ch)) {
    echo 'Error:' . curl_error($ch);
}
curl_close($ch);