Send Email with SendGrid using Web Api php - php

Question

I am confused with here with $pass and $api_key
are they same, because at first $pass is assigned with password of the SendGrid's username but then api_key is assigned with $pass.
if they are same they where we would use that api_key that we generated on SendGrid?
Please Help!!!
<?php
$url = 'http://sendgrid.com/';
$user = 'USERNAME';
$pass = 'PASSWORD';
$params = array(
'api_user' => $user,
'api_key' => $pass,
'to' => 'example3#sendgrid.com',
'subject' => 'testing from curl',
'html' => 'testing body',
'text' => 'testing body',
'from' => 'example#sendgrid.com',
);
$request = $url.'api/mail.send.json';
// Generate curl request
$session = curl_init($request);
// Tell curl to use HTTP POST
curl_setopt ($session, CURLOPT_POST, true);
// Tell curl that this is the body of the POST
curl_setopt ($session, CURLOPT_POSTFIELDS, $params);
// Tell curl not to return headers, but do return the response
curl_setopt($session, CURLOPT_HEADER, false);
curl_setopt($session, CURLOPT_RETURNTRANSFER, true);
// obtain response
$response = curl_exec($session);
curl_close($session);
// print everything out
print_r($response);
?>

Answer 1

There's a few issues with what you're trying to do:
You should never send an API call to sendgrid.com, only api.sendgrid.com
It looks like you're trying to use the v2 API with the Params. Since you're setting up a new script, you should use the v3 API which uses proper body JSON arguments, and is RESTful.
Instead of setting up your own script, have you looked at the SendGrid PHP Library?
For authentication in a script, you should always use an API Key, not your master username & password.
It looks like you got a really old example script for testing. Where did you get that from?