Email Validation: How It Works and Why It Is Important

Email Validation: How It Works and Why It Is Important

On a daily basis, roughly 350 billion emails are sent around the world across the internet. It is the lifeblood of business communication and the sharing of vital information between individuals and customers alike. Since its birth in 1972, the way in which emails are transmitted has changed drastically; transforming from simply transferring a document to a recipient computer via a network connection to being done through a vast array of network connections over the internet via dedicated protocols.

One of the biggest headaches that people face in modern times is confirming that recipients have correctly received your messages when attempting to reach out to a large number of people. Roughly 31 billion emails are bounced or do not get received by the intended recipient.  On an individual scale, if an email fails to deliver, you will typically receive a failed delivery email bounce right back at you and you will know immediately if you made a mistake. However, when performing any type of large scale outreach campaign, bounced recipients can easily be missed while also hurting your domain reputation. Ensuring that the email data you are using for your business is accurate is critical. That is where the process of email verification comes in.

In this article, we will be covering what this term means and why it is critical for email addresses to be properly verified before attempting any sort of outreach campaign that utilizes a large amount of emails that you have not attempted to make contact with yet. Knowing what is going on behind the scenes will help you out with deciding on a verification service as knowing what certain terminology and phrases mean can give you insight on what specifically a service does and perhaps why it is different from the competition

What is email verification?

To put it simply, email verification is the process of authenticating email addresses to ensure that they exist and are able to receive messages. Verification of your emails can result in up to an 81% reduction in overall bounced emails, but how exactly does this process work? We will be covering the various ways that verification services determine if an email address is good or not, but essentially this is done by confirming if the address is following the proper syntax needed to be valid, confirming if the domain attached to the address exists, checking if there is an open and valid mailbox that can be pinged and receive outside mail (as many businesses will utilize internal email addresses that can only receive mail from other addresses on the same domain) and assessing the risk of an address (If this address has been marked for spam abuse).

Why Verify?

Why email validation is so important

Email verification is a very straightforward process that can save businesses time and money by ensuring that outreach attempts are not being wasted upon non-existent people and email addresses. Through the utilization of validation providers and services that specialize in email deliverability, this can greatly improve your metrics on email delivery & overall outreach.

Alongside internal metrics for measuring internal performance with outreach, a big reason why all businesses should be verifying their emails is to ensure that they are not accidentally reaching out to spam traps. A spam trap is an active/abandoned email address that is used to entrap and expose illegitimate senders who reach out to an address on a particular list who has not received the proper permissions to do so. Reaching out to these addresses can have some negative consequences, ranging from your ISP hard bouncing a piece of mail back to you, making you aware of a bad email so you can remove it from your database or completely blacklisting your sending domain by a majority of email providers. These end results can be a disastrous situation for a company when managing an outreach campaign as well as general business communication, as this can affect your domain reputation, deliverability, open rates, click rates, and conversion rates going forward on all emails you send out. Any negative email reputation can result in messages automatically getting marked as spam and sent directly to a receivers spam folder, so email verification can be considered a vital part of any data cleaning process that a business should be engaged in.

Verifying emails you plan to use for outreach also helps tremendously with ensuring that your domain avoids having too many hard bounces. A hard bounce is when an email is sent to an address that either doesn’t exist or previously existed and was deleted at a later time. Hard bounced emails will drastically affect your email deliverability rate in a negative way and can cause adverse effects to all emails sent out from your domain going forward. Many of these verification services also have access to millions of known spam trap domains, easily preventing you from accidentally reaching out to known bad addresses. Performing regular email integrity checks via verification can help prevent these damages from occurring.

In short, we established that email verification is a valuable resource to take advantage of. It is generally a low expense cost for a business to utilize when performing any type of growth focused outreach campaign. But how often should a company validate their database of contacts?

The Importance of Consistent Validation

Things change as time goes on. The same can be applied to business data as companies and businesses are constantly changing and evolving over time. Contacts within your CRM may change positions or start working elsewhere and it can be difficult to keep track of when these changes occur. Email validation is an easy and consistent way to identify and adjust data that becomes stale. Lets go over some of the reasons why portions of your contacts might go bad.

Why Email Addresses Become Invalid

Why Email Addresses Become Invalid Infographic
Why email addresses become invalid.

Your CRM is only as good as the data held within it. Ensuring that contacts are up to date and current is critical for businesses so that any outreach attempts don’t fall on deaf ears. Some of the most common reasons for once valid data to become invalid is as follows.

1) Email owner changed email provider/service

It’s common for people over the years to create new addresses and abandon older addresses if they have moved on with their career or lost a previous account due to various reasons. This could be due to previously using a paid email service (an address tied to a registered domain, services such as IceWarp, FastMail, etc). These services typically will get deleted after 90 or marked as dead inboxes by providers within 120 days or so.

2) Email owner switched position within a company

Occasionally an email address will go dormant due to a change in position internally at a company. Most often, this will not result in a change of email address but within many industries it is common to have separate domains for separate departments at a company (I.E an address changing from to or )

3)  Email owner has left their current position

Within the world of business, people changing jobs and working for different companies is very commonplace. Some people will change careers frequently due to contracts or other short term work agreements so refreshing your database is critical to ensure any attempted contact doesn’t result in a hard bounce.

4) Domain is dead

Domains do not last forever. Occasionally companies will decide to switch over their parent websites to a new domain, and with that old domain goes all associated emails with it if they do not keep their web server.

Performing routine email verification on your database is a habit that all companies should adopt in order to maintain a healthy index. Every day information regarding individuals and companies are changing and it is important to ensure that your database reflects these shifts.

How Email Verification Tools/Providers Work

We have covered what email verification is and why it is essential for your business to engage in such practices in order to maintain your domains reputation with email providers and ISP’s, but how are email verification providers actually performing these services? Let's take a deeper dive into each step of the process and see how this can be done.

Email Syntax & Formatting Check

The breakdown of the standard format of an email address

Since the inception of the Simple Mail Transfer Protocol (SMTP) in 1982, every single email address on the internet is required to follow a standard syntax in order to send and receive communication utilizing this protocol. A valid email address has the following four components.

1) Recipients Name

The recipient's name is the string that comes before the @ symbol in an email address. The maximum length of this name is limited to 64 characters and needs to be following the American Standard Code for Information Interchange (ASCII) table and only consist of uppercase and lowercase letters in English (A-Z, a-z), digits from 0 to 9, and a limited set of special characters (! # $ % & ' * + - / = ? ^ _ ` { |). For many email addresses, this string is usually either the name of the person who owns the email, the name of a department/ or role within a business, or a completely custom string chosen by the owner of the address.

2) The @ symbol

The @ symbol is the local part of the address and separates the recipient's name from the domain and is necessary for SMTP communication.

3) Domain Name

The domain name of an email address specifies the exact location of the email server this address is being hosted at. When an email is sent out, the local Mail Submission Agent (MSA) determines where in the server structure the mailbox is located in the specified domain and hands it off to be received to the proper address.

When a tool or provider is checking if an email is following the correct syntax, they will verify that it has met the following criteria and determine if it is indeed a correctly structured address or not. If this email passes this step it will move on to be further analyzed and checked for verification, but if the syntax is off the email in question will be marked as invalid.

Domain Confirmation

How domain validation works.

Once an email has been verified to have the proper syntax, it will be moved onto the process of verifying that the domain attached to the address exists and is able to receive emails. Typically, the process of validating a domain consists of performing either of the following actions.

1) Ping Testing

The term ping refers to the process of testing the amount of time it takes for a packet of information to be sent to a server and then received back. This is a quick and efficient way to determine if a particular domain actually exists or not. If you attempt to ping the domain of an email address and you receive a response, this is a sign that this domain is indeed tied to a website or server. If a ping is attempted and there is no response, this typically will indicate that this is an invalid domain and therefore an invalid email.

2) Domain Lookup

This method is mostly done on a smaller scale but still verifies if a domain is valid or not. This is done by simply attempting to connect to a domain to see if it leads to a dead end or not. If a server IP address cannot be found when attempting to connect to a domain, it does not exist or has been shut down. If you can access the domain, this verifies if it exists or not.

3) Bounce Test

This is a method that we strongly recommend not doing as it requires attempting to directly contact a domain via sending an email to an address. This will quickly and accurately let you know if an inbox exists or not, but the possibility of hard bounces is far too great to do on a large scale. A majority of email verification services will not perform bounce tests for this very reason.

4) Live Site Domain Checks

This is a fairly straightforward approach to get a better idea on if an inbox exists or not. Simply attempt to connect to the domain attached to an email address through a web browser. If you can connect to the website and do not receive a 404 error or a parking site, than there is a good chance that there is an email server associated with it.

Once the domain has been verified to exist, an email verification provider or tool will then proceed to verify if there is a valid mailbox attached to the domain.

Mailbox Validation

Once an email address string has been verified to both follow the standard protocol and is linked to an existing domain, an email verification provider will then attempt to determine if a valid mailbox exists in this domain. The simple way for anyone to determine if a mailbox exists is to simply attempt to send a message to this address. For obvious reasons, this is a less than ideal solution to this problem as it requires you to reach out to an address and risk this exchange being your first contact with the owner. Thankfully, there is a much more elegant solution to this that these tools and services utilize to verify the existence of a mailbox.

Without getting into the details of how this is done specifically, the basic process is to attempt to directly connect to a domain's web server using a script that will do the following.

  1. Connect to the server of the domain
  2. Run a command to verify the records hosted on the domain
  3. Attempt to connect to the port responsible for handling email traffic
  4. Send a request to the server containing the email address in question

This is a greatly simplified explanation of how this is done, but by following these steps a provider will quickly and easily verify if an email address on this server exists based upon how the server responds to these requests. For example, a tool or provider will be able to tell if an email server exists by the time they reach step 3 if they are unable to connect to the port responsible for handling email traffic. Thanks to SMTP, an email server can only exist on a server if it can be connected to via port 25 so this greatly simplifies the trial and error of finding out where a mailbox could be stored.

At step 4 of this process, the response that is sent back from the server will determine if the address exists or not. If an email address has passed all these verification steps, then it is almost certain that it is a valid email address that can receive emails.

Choosing a Verification Service

Considerations for choosing a validation service.

There are a wide variety of email verification services available online and thankfully, many of them work well and are reliable. But a question comes to mind about which one of these services might work best for your needs. Every individual and business has specific needs for what they choose to use as a tool. Some services might work best for your workflow while others might work best for their simplicity so lets go over some things to consider when choosing a provider.

1) Online Availability

For most practical purposes, an online service that handles email verification is the most convenient way to handle verifying a list of emails. Most verification services operate in this manner, where they host an online platform through their website. From here, all you do is simply upload/copy whatever list you have, confirm your list, wait, then download your results from there. For individuals or small businesses, having a service similar to this is ideal if you do not frequently need to verify a list of emails as they typically are inexpensive and only require you to pay for what you use.

Another great benefit of an online verification service is that it does not require you to utilize your ISP services outside of accessing the platform and uploading your list. Email verification requires your IP pinging multiple separate servers across the world and can potentially harm your email deliverability if there is too much activity coming from your connection.

2) Complex Catch All Verification

As stated previously, Catch All emails refer to server domains that are configured to accept all incoming mail no matter if the target address exists or not. These emails get sent to an inbox that accepts all mail that cannot be delivered to an existing inbox, but these inboxes tend to be clustered as they tend to get bombarded with spam and requires an admin to manually go through and redirect lost emails to their designated user.

Catch all emails cannot be ‘verified’ in the same way as server domains configured in a standard way, but there are methods that verification services utilize to get a better idea on if these addresses do exist or not. When deciding on a verification service, it’s a good idea to pay attention to reviews or features listed on their site to determine how they handle this.

3) Multiple Methods of Verification

The most reliable services will perform multiple verification methods to ensure their results are as accurate as possible. Syntax verification, Live domain confirmation, Ping tests, bounce checks, all of these methods should be implemented in some way by the service to ensure that your list is being thoroughly tested. Some services will only do a few of these types of tests so it’s good practice to explore a services site and find out what their methodology is.

4) API and CRM Integration

Integrations are a critical functionality to look out for when considering a verification service. For many large businesses, it can be a complex task to verify their CRM database through a web platform alone as it requires multiple steps in order to pull information, verify it, and then re-implement this information back into their database. Many verification services will offer API documentation and direct CRM integration to easily push and pull verification requests easily.

5) Single Email Verification

Situations will occasionally come up where you will need to quickly and easily verify a single email. Having this option can be extremely handy in niche situations so it’s a good idea to keep an eye out for this type of feature for a service before trying them out.

In Summary

The process of verifying email addresses is an important step for any business to make when launching an outreach effort. These campaigns cost time, money, and resources for a company, so it is money down the drain to not verify that every email you send out is received by an inbox and to the owner in question. Thankfully in the modern age of the internet, the process of verifying these addresses can be as simple as utilizing the services of a company or tool who specializes in the process, so you can be assured that it is indeed possible to make sure that your lists are only filled with accurate addresses.

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