Email-domain-verifier NPM

email-domain-verifier

A npm package that verifies email domains via dns mx records and attempting smtp connection

Installation

npm install email-domain-verifier --save

Usage

import { verifyEmailDomain } from 'email-domain-verifier'


await verifyEmailDomain('mailbox@gmail.com', { requireSmtpOrMx: true })
//  {
//    verified: true,
//    mxVerificationSucceed: true,
//    smtpVerificationSucceed: undefined
//  }

await verifyEmailDomain('mailbox@garbage.domain', { requireSmtpOrMx: true })
//  {
//    verified: false,
//    mxVerificationSucceed: false,
//    smtpVerificationSucceed: false
//  }

Options

{
  mxNotRequired?: boolean,         // Verify via smtp connection check only 
                                   // Mx records would still be resolved for smtp check
                                   // default: false

  smtpNotRequired?: boolean,       // Verify via dns mx records check only
                                   // default: false

  requireSmtpOrMx?: boolean,       // Require at least one check to succeed
                                   // default: false

  smtpConnectionTimeout?: number,  // Timeout for smtp connection in milliseconds
                                   // default: 1000

  useCache?: boolean               // Use in-memory lru cache
                                   // default: true
}

Details

Cache

Simple in-memory lru cache
Verification with { useCache: false } doesn't fetch cache, but still updates it
Only successful verifications get stored in cache
Max cache size is 1000 and ttl is 24 hours

Smtp check

Conducted via attempting tcp connection to popular smtp ports
Ports list is [ 25, 456, 587, 2525 ]
The check is successful if at least one of these ports is open on any of the mail exchange servers
In addition to mail exchange servers, these ports are scanned on `${domain}` and `smtp.${domain}`
Most public ISP block requests to port 25, so port 25 scan might not work from your home, but should work from your server