src/SendPulseApi.php
public function smtpAddDomain( $email ) {
        if( empty( $email ) ) {
            return $this->handleError( 'Empty email' );
        }

        $data = array(
            'email' => $email
        );

        $requestResult = $this->sendRequest( 'smtp/domains', 'POST', $data );

        return $this->handleResult( $requestResult );
    }
public function smtpAddDomain( $email ) {
        if( empty( $email ) ) {
            return $this->handleError( 'Empty email' );
        }

        $data = array(
            'email' => $email
        );

        $requestResult = $this->sendRequest( 'smtp/domains', 'POST', $data );

        return $this->handleResult( $requestResult );
    }
SMTP: add new domain

@param $email
@return mixed|stdClass