WordPress REST API send email SMTP in with PHPMailer

function.php

<?php

function sendWithPhpMailer($subject, $body, $reply) {
    require(ABSPATH . WPINC . '/class-phpmailer.php');
    require(ABSPATH . WPINC . '/class-smtp.php');

    // date_default_timezone_set( 'America/Sao_Paulo' );

    $blogname = wp_strip_all_tags( trim( get_option( 'blogname' ) ) );
    $smtpHost = wp_strip_all_tags( trim( get_option( 'smtp_host' ) ) );
    $mailPort = wp_strip_all_tags( trim( get_option( 'smtp_port' ) ) );
    $smtpUser = wp_strip_all_tags( trim( get_option( 'smtp_user' ) ) );
    $smtpPass = wp_strip_all_tags( trim( get_option( 'smtp_pass' ) ) );
    $mailTo = wp_strip_all_tags( trim( get_option( 'mail_to' ) ) );

    $send = false;
    $mail = new PHPMailer;

    try {
        $mail->IsSMTP();
        $mail->SMTPDebug = 0;
        $mail->Sender = $smtpUser;
        $mail->CharSet = 'utf-8';
        $mail->SMTPSecure = 'tls';
        $mail->SMTPAuth = true;
        $mail->Port = $mailPort;
        $mail->Host = $smtpHost;
        $mail->Username = $smtpUser;
        $mail->Password = $smtpPass;
        $mail->Subject = $subject;
        $mail->From = $smtpUser;
        $mail->setFrom($smtpUser, $blogname);
        $mail->addReplyTo($reply);
        $mail->addAddress($mailTo);

        // Attachments
        // $mail->addAttachment('/var/tmp/file.tar.gz');

        $mail->isHTML(true);
        $mail->Body = $body;

        $send = $mail->Send();

        $mail->ClearAllRecipients();
    } catch (Exception $e) {
        echo "Message could not be sent. Mailer Error: $mail->ErrorInfo \n";
        echo "Error: $e";
        return false;
    }

    return $send;
}

function sendContactMail( $request ) {
    $response = array(
        'status' => 304,
        'message' => 'There was an error sending the form.'
    );

    $parameters = $request->get_json_params();

    if ( count($_POST) > 0 ) {
        $parameters = $_POST;
    }

    $blogname = wp_strip_all_tags( trim( get_option( 'blogname' ) ) );
    $contactName = wp_strip_all_tags( trim( $parameters['contact_name'] ) );
    $contactEmail = wp_strip_all_tags( trim( $parameters['contact_email'] ) );
    $contactPhone = wp_strip_all_tags( trim( $parameters['contact_phone'] ) );
    $contactMessage = wp_strip_all_tags( trim( $parameters['contact_message'] ) );

    if ( !empty($contactName) && !empty($contactEmail) && !empty($contactPhone) && !empty($contactMessage) ) {
        $subject = "(New message sent from site $blogname) $contactName <$contactEmail>";
        $body = "<h3>$subject</h3><br/>";
        $body .= "<p><b>Name:</b> $contactName</p>";
        $body .= "<p><b>Email:</b> $contactEmail</p>";
        $body .= "<p><b>Phone:</b> $contactPhone</p>";
        $body .= "<p><b>Message:</b> $contactMessage</p>";

        if ( sendWithPhpMailer( $subject, $body, $contactEmail ) ) {
            $response['status'] = 200;
            $response['message'] = 'Form sent successfully.';
        }
    }

    return json_decode( json_encode( $response ) );
    exit();
}

add_action( 'rest_api_init', function () {
    register_rest_route( 'contact/v1', '/send', array(
        'methods' => 'POST',
        'callback' => 'sendContactMail'
    ));
});

I guess you forgot to create $request variable of WP_REST_Request

function sendContactMail(WP_REST_Request $request) {

line 54

$blogname is used in line 72 but not set in that function (set in sendWithPhpMailer). Should assign that variable in the function before using

thanks guys!!

$blogname is used in line 72 but not set in that function (set in sendWithPhpMailer). Should assign that variable in the function before using

on line 66 @rjriel https://gist.github.com/nandomoreirame/5966bc4b12588904c214277328ba701a#file-function-php-L66

Thank U