Usually, free email verification means sending an email to see if it will bounce. However, you can verify an email address without sending an email. In fact, there are two ways to do it: an easy way and a hard way.
As you may have guessed, the hard way is free. The easy way costs a little bit. But, you save a ton of time, effort, and energy. And, you get much more information about the email address you’re checking.
Each email validation method has its uses. So, we’ll cover both, starting with the basics.
Why Verify an Email Address?
Email verification might seem unnecessary. If the email is invalid, you just get an email that lets you know, right? Not quite.
Sending emails to invalid email addresses can damage your domain or IP address reputation. Your sender reputation is how email services (Gmail, Microsoft, Yahoo!, etc.) track your email sending behavior and determine if you’re a trustworthy sender.
If you send too many emails to invalid email addresses, spam traps, and catch-all email addresses, email services will notice. Then they’ll start sending your emails to the spam folder or rejecting them altogether.
Also, if you’re sending marketing emails, sending to an invalid email address is a waste of time and money. So, email verification makes your marketing email program more profitable.
In any case, sending emails to invalid email addresses is useless. So, it’s silly NOT to verify email addresses.
Free Email Validation
You can verify email addresses for free. All you need is access to the command line in your operating system and some simple software.
These are the basic steps in the free email validation process:
- Do a DNS lookup to find out if the email server exists.
- Identify the primary email server.
- Ask the server if the email address you have is valid.
You only need to know a few commands to complete all of these steps. You’re mostly just gathering information from the receiving email server. Here’s how to do it:
Use the dig or nslookup command to get information about the receiving email server
This step verifies that the receiving email server exists, and gets information about that email server.
There are two commands that gather information from the DNS records: dig or nslookup.
Type this into your command line to use the dig command:
dig [email server] mx
Replace [email server] with everything after the “@” symbol in the email address. So, if you wanted to get information about a Gmail address, you’d type: dig gmail.com mx
Type this into your command line to use the nslookup command:
nslookup -q=mx [email server]
Replace [email server] with everything after the “@” symbol in the email address. If you wanted to get information about a Gmail address, you’d type: nslookup -q=mx gmail.com
When you type one of these commands, you will get a bunch of information that you won’t recognize unless you’re familiar with the technical aspects of email. All you need to look for is a list of the email servers.
If you used the dig command, the list will look like this:
gmail.com. 5 IN MX 20 alt2.gmail-smtp-in.l.google.com.
gmail.com. 5 IN MX 40 alt4.gmail-smtp-in.l.google.com.
gmail.com. 5 IN MX 30 alt3.gmail-smtp-in.l.google.com.
gmail.com. 5 IN MX 10 alt1.gmail-smtp-in.l.google.com.
gmail.com. 5 IN MX 5 gmail-smtp-in.l.google.com.
If you used the nslookup command, the list will look like this:
gmail.com mail exchanger = 20 alt2.gmail-smtp-in.l.google.com.
gmail.com mail exchanger = 40 alt4.gmail-smtp-in.l.google.com.
gmail.com mail exchanger = 5 gmail-smtp-in.l.google.com.
gmail.com mail exchanger = 30 alt3.gmail-smtp-in.l.google.com.
gmail.com mail exchanger = 10 alt1.gmail-smtp-in.l.google.com.
Find the line with the lowest number after “MX” or “mail exchanger.” On these lists, that would be “5 gmail-smtp-in.l.google.com.” The line should not have “alt” in it. This is the primary email server.
Next, we’re going to connect to that server and find out if the email address we have is valid.
Use Telnet connect to the email server
For this step, you’ll need to use Telnet commands. Setup Telnet on your computer before you do this part.
Use the Telnet command to connect to the email server. This is the Telnet command:
Telnet [server SMTP name] 25
Replace [server SMTP name] with everything after the number on the line. For instance, to connect to the Gmail server we looked up in the last section, the command would look like this: Telnet gmail-smtp-in.l.google.com 25
Make sure you include “25” after the server name. This specifies that you’re connecting through the standard SMTP port.
You should get a message that tells you that you’re connected to the email server. If you don’t, then you most likely have a mistake in your command.
Once you’re connected, use the HELO command to talk to the email server. This is the HELO command:
HELO [email server]
For a Gmail address, the command would look like this: HELO Gmail.com
You should get a response that starts with “250.” Again, it’s most likely because of a typo if you don’t. Once you’re connected to the email server, all you need to do is verify that the email address is valid.
Check the email address
The first part of checking the email address is making sure that the email server can accept messages.
Use the mail from command to ping the receiving server. This is the mail from command:
mail from:<[your email address]>
Replace [your email address] with a valid email address other than the one you’re verifying. For us here at Searchbug, the command would look like this: mail from:< firstname.lastname@example.org>
If you get a response with “250 … OK,” the server can receive emails. You can move to the last step.
Use the rcpt to command to verify the email address. This is the rcpt to command:
rcpt to:<[email address to be verified]>
Replace [email address to be verified] with the email address you’re verifying. So, the command might look like this: rcpt to:<email@example.com>
If the email exists, you’ll get a “250 … OK” message. If the email address does not exist, you’ll get a response that starts with “550,” like this one: 550-5.1.1 The email account that you tried to reach does not exist.
If the email address gets a “250 … OK” response, it’s safe to email. Otherwise, skip it.
Clearly, this is not quick email verification. And, it’s not ideal for bulk email validation. But, it’s free email verification.
If you’re not up for going through this process whenever you need an email checker, do things the easy way.
Email Verification Services
Email verification services aren’t free. However, they’re much faster and easier than using the command line and Telnet. And, they get you additional details about the email address.
There are email verification services for everyone. If you need an email checker to handle just a few email addresses, a simple email verification tool will work.
If you need to validate email lists, you’ll need more powerful email verification services. These services are generally separated into two categories: batch processing and data integration. Here’s how they work.
Bulk Email Verification
Bulk email verification, or batch processing, is ideal if you have email lists that you need to clean. It’s an ideal option if you have email addresses that you’ve already collected and entered into a spreadsheet.
All you need to do is ensure that the email addresses are stored in a .txt, .csv, or Excel sheet. Then, upload that file to your batch processor. You’ll usually get your results back in a matter of minutes. But, it may take longer for very large lists.
Batch processing will tell you if the email is valid. But, it also tells you if the email is disposable or toxic. So, email verification services protect you against valid email addresses that are unsafe to send to.
Your results will be delivered in a .csv file that you can upload to your email program, and send away.
Data integration works best if you use software to manage your email lists and customer data. CRM software is ideal for data integration. But, some email software can handle data integration, as well.
Data integration uses an API to connect to your data aggregator or data reseller’s system. It’s the same system that your data partner uses for batch processing. But, the API automates the process of uploading your lists.
Most data reseller APIs integrate with a unique URL. The integration is simple. You can probably do it yourself. But, if you have an IT person or developer on your team, they can complete the integration in a few minutes.
Once you have data integration setup, your CRM system will automatically send new email addresses out for verification before you send emails to those addresses. It’s automated email verification.
Those are the easy ways. Usually, it costs less than a penny per email to verify emails in bulk or with data integration. So, the time, effort, and energy you save is more than worth the cost of the email verification service. Plus, you get more thorough email validation.
If it feels like too much work to validate emails for free, check out the Searchbug batch email deliverability check and email address verification API. It’s the easy and affordable way to get dependable data.