CodeIgniter already comes with an email library. For more information on how to use CodeIgniter with SendGrid, check it out on their documentation page.

It is important to use the correct end of lines using “crlf” => “\r\n” and “newline” => “\r\n”.

$this->load->library('email');
$this->email->initialize(array(
'protocol' => 'smtp',
'smtp_host' => 'smtp.sendgrid.net',
'smtp_user' => 'sendgridusername',
'smtp_pass' => 'sendgridpassword',
'smtp_port' => 587,
'crlf' => "\r\n",
'newline' => "\r\n"
));
$this->email->from('your@example.com', 'Your Name');
$this->email->to('someone@example.com');
$this->email->cc('another@another-example.com');
$this->email->bcc('them@their-example.com');
$this->email->subject('Email Test');
$this->email->message('Testing the email class.');
$this->email->send();
echo $this->email->print_debugger();