(Node.js) Verify Email Recipients

A way to possibly determine valid/invalid email addresses. I would recommend being very careful about doing this because your IP address may be flagged as a potential spammer by the mail server (because you are probing for valid/invalid email addresses). This Chilkat functionality existed for many years, before this kind of activity became a problem. The functionality remains only because it is useful for some to test with their own SMTP servers.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    var mailman = new chilkat.MailMan();

    // SMTP connection settings...
    mailman.SmtpHost = "smtp.example.com";
    mailman.SmtpUsername = "MY_SMTP_USERNAME";
    mailman.SmtpPassword = "MY_SMTP_PASSWORD";
    mailman.SmtpSsl = true;
    mailman.SmtpPort = 465;

    // Create a new email object
    var email = new chilkat.Email();

    email.Subject = "This is a test";
    email.Body = "This is a test";
    email.From = "myemail@example.com";
    var success = email.AddTo("person1","person1@example.com");
    success = email.AddTo("person2","person2@example.com");
    success = email.AddTo("person3","person3@example.com");
    // The SMTP server smtp.example.com won't know anything about an email address @somewhere_else.com
    success = email.AddTo("person3","person4@somewhere_else.com");
    // ...

    // Verify recipients.
    // **** See the warning about using this API method in the description above.
    // (An SMTP server only knows valid email address for its own domain.  For example,
    // smtp.example.com *may* only know if person1@example.com is valid or invalid, but does
    // not know anything about the validity of email addresses having other domains.)
    var badAddrs = new chilkat.StringArray();
    success = mailman.VerifyRecips(email,badAddrs);
    if (success !== true) {
        console.log(mailman.LastErrorText);
        return;
    }

    var i = 0;
    while (i < badAddrs.Count) {
        console.log(badAddrs.GetString(i));
        i = i+1;
    }

    console.log("done.");

}

chilkatExample();