What Is ​​a Valid Email Address?​​ An Actionable Guide to a Clean Email List

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Being an email marketer means being responsible for building a list of subscribers, creating engaging content, and mastering A/B testing, to start. Through it all, the most critical aspect is knowing what is the best email address to use in your emails, with the answer being — a valid email address.

A valid email address follows the correct format, is active, and belongs to an email domain. Validating recipients’ email addresses will ensure they are active and ready to receive your emails. When your messages reach the correct inboxes, it reduces email bounces and improves customer engagement.

To effectively use email addresses in your campaigns, it’s essential to know their formats, how to build a valid email address list, and how to improve the success of your email campaigns. Let us show you the ropes.



What is a Valid Email Address Format?

When handling large email lists, all email addresses could look similar. The only way to differentiate is to know the valid email address format. Below, you’ll find the common email address formats.

Email addresses have three parts:

  • Username (prefixes the ‘@’ symbol): Also called local-part, the username is associated with a mailbox that is owned by a person — for example, Name_Surname@gmail.com. Usernames can consist of 64 characters and include uppercase and lowercase letters (A-Z, a-z), numbers (0-9), and special characters (#,$,&,*, etc). 
  • @ Symbol: This is the part that differentiates a username from a domain name. It’s also impossible for an email address to be valid without the ‘at’ symbol. A fun fact is that this symbol is also known as ‘Monkey’s Tail’ in Dutch.
  • Domain name (Suffixes the ‘@’ symbol): The domain name refers to the mailbox providers such as Google, Yahoo, Outlook, etc. It can be up to 253 characters long and contain uppercase and lowercase letters, digits (0-9), a hyphen (-), and a period (.). 

Valid & Invalid Email Address Format Examples

Although all email addresses follow the same format, not all are considered valid. Sometimes, subscribers can make accidental mistakes like typos and misformatting.

 A valid email address format looks like this:

  • Johndoe@domainname
  • Janedoe@gmail.com
  • Lastname_surname@businessname
  • Surname1234@yahoo.com

An invalid email address looks like this:

SyntaxExampleReason
Username@ron.smith5234Has no username 
Symbolsmithjones.876.gmail.comContains no symbol
Domain namevicktorhaley@.orgMissing domain name
Email addresslovisa_han1993@gmil.comMisspelled email address
Invalid email address examples

Other reasons for invalid email addresses can be if an inbox provider went out of business, a server is down, or the recipient no longer uses the email address. 

Your email campaigns should target valid email addresses only, and to make sure they are active, you need to validate them. Let’s see how to check whether you are sending to the right destinations. 


How to Check if a Recipient Email Address Exists?

Even when an email address is well-formed and looks normal, it doesn’t mean it exists. And a non-existing email address can lead to bounces or spam complaints. Here are the best approaches to check if an email address is still in existence:


1. Use a Trusted Email Verification Tool

Email verification tools run various validation checks such as syntax, domain, and MX record checks to ensure you’re sending emails to the right addresses. This is especially helpful with larger and un-updated email lists. 

There are two types of email verifiers you can choose: computer programs and online services. If your email addresses require a larger storage space or access to the internet, then online services will be the best choice. Certain email verifiers even allow for integrations with email marketing tools, creating a seamless workflow for your email campaigns. 


2. Send Test Emails 

This is a direct way of testing email address validity by sending individual emails to check if they bounce. However, for larger email lists, this could mean higher spam complaints, reduced sender reputation, and poor deliverability. A possible solution is to create dummy email accounts to test the validity of email addresses.


3. Check the Address on Google 

This method might work if you have fewer emails to test — type the recipient email address in Google, and it could show if it’s valid. People use their email addresses publicly, which makes it easier to sweep through the database and find an existing email address.


4. Check Disposable Email Domains

Using disposable emails is a common pattern in people who do not wish to disclose their original email address. Most sign up with this temporary email address to receive promotional emails. To spot a disposable address, use an online disposable email verifier such as Abstract API.


5. DNS Lookup

The Domain Name System (DNS) acts as a storage of email addresses for quick searches (think phonebooks). It translates human-readable domain names into machine-readable language. This is how DNS helps you find important information about your recipients’s addresses such as Domain availability, creation date, and owner details. In short, DNS helps you look up whether a recipient’s email address exists and is valid.

When you validate recipient email addresses, you’ll have better chances of getting your emails delivered. Plus, removing invalid recipient email addresses is the first step in what should be regular email list hygiene.


How Will an Invalid Recipient Email Addresses Impact Your Email Marketing?

Invalid recipient email addresses do not match with the existing email account you want to target. This means when you send emails, they do not get delivered, damaging your sender reputation.

Here are several reasons why not checking your recipients’ email addresses can pose a threat to your email marketing:

  • Wasted resources: Not validating recipients’ email addresses means you will be sending emails that will never reach the inboxes. Especially if you’re using an email service provider, a cluttered email list equals higher costs (most ESPs charge by email list size).
  • Bounce rates: Sending emails to invalid addresses could lead to higher bounce rates. ISPs closely monitor bounce rates, which can impact your sender reputation negatively.
  • Reduced open rates: Invalid recipient email addresses reduce deliverability and open rates. Constantly sending emails to the wrong addresses can make ISPs suspicious of your attempts.
  • Spam Traps: Spam traps or honey pots are email addresses used by ISPs to identify senders with malpractices. Regularly sending emails to invalid addresses could alert the authorities about your bad email marketing practices
  • Lower engagement rates: When emails don’t reach your recipients, it’s hard to track email campaign metrics such as click-through rates and conversions. Without this data, you could create misinformed email campaigns in the future.
  • Risk of blacklisting: Continually sending emails to invalid addresses can trigger spam filters and ISPs blacklisting your domain. Another reason you could face blacklisting is when you send unsolicited emails to people. This habit could increase the spam complaint ratio, leading to a permanent ban in a few cases.

As a general rule, the spam complaint rate should fall below 0.1%.

Some ESPs are particular about this and require lower ratios. For example, at Campaign Refinery, we advise our customers to maintain a spam rate lower than 0.05%. Our clients have lower spam complaint rates than the industry standard due to their excellent sender reputations and our smoothly-running software solutions.

There are many different resources on what is a valid email address for new email marketers out there. To make it easier, we’ve created a guideline for building a valid email address list below.


Building a Valid Email Address List: 3 Easy Steps 

An email address list consists of all the email addresses you’ve collected from your customers or prospects. Collecting emails is only the first step of the email marketing process. After that, you need to verify the list to ensure the emails are valid. This process is called email validation. 

Here are 3 steps to build a valid email address list:

1. Build opt-in forms: Opt-in forms help collect information from interested visitors, ensuring consent. This makes data more accurate since the information is permission-based. 

2. Perform an email syntax check: Syntax checks are useful in extracting valid email addresses from a list. To do this, check for recipient addresses that miss the ‘@’ symbol or have misplaced characters. 

3. Work with an ESP: ESPs help keep your email lists clean and updated at all times. By this, we mean they help you avoid sending emails to inactive subscribers, reducing the number of bounced emails.

With that in mind, let’s go over one the most critical parts of an email marketing campaign — email list cleaning.


Why is Email List Cleaning Important?

A clean email list helps increase open rates, deliverability, and improve email metrics. 

Start by removing invalid and fake email addresses, low-activity subscribers, and subscribers with high complaint rates.

Repeat the cleaning process at least once a year. The frequency also depends on your email list size and business type. When considering how often to clean your lists, look at your bounce rates. If the bounce rates are higher, it indicates that your email list needs cleaning, irrespective of its size. Additionally, reviewing your open rates, unsubscribes, and spam complaints will give you better clarity on which audience segment is engaging with your campaigns.

But — should you clean email lists manually? Well, you can, but for higher accuracy, we recommend an online service or an ESP. Manually cleaning lists can take up too much time and increase the possibility of errors. Whereas an online tool or a provider will have the necessary features to conduct larger checks. 


Do Email Service Providers Help With Email List Cleaning?

At Campaign Refinery, our primary goal is to consistently produce and maintain high deliverability rates for our clients. And this starts with email list cleaning: removing undeliverable email addresses, avoiding blacklists, and eliminating hard bounces. Additionally, we keep your domain safe, regardless of the number of IP addresses you have assigned to it.

We know that for an email marketer, a clean email list and a reliable IP experience mean higher ROI. 

That’s why at Campaign Refinery, we:

  • Make domain authentication and email validation mandatory (our clients’ email volume is signed with DKIM by default).
  • Use an exclusive feature to clean email lists and maintain high deliverability rates (keep reading to know more about our feature!).

Our sophisticated software solutions provide elite results — check out our offer and apply to become a successful member of the Campaign Refinery family!

Your email lists are the biggest resource in your email marketing, and maintaining email list hygiene is a key factor in your success. But you should never neglect other clean email marketing practices to keep your operation flowing. 


Everything You Should Know About Good Email Marketing to Start Your Ops

Along with our automatic list-cleaning feature that protects you from harmful emails even before you hit the send button, our powerful software makes your email marketing efforts shine like never before. Our clients’ deliverability performance has improved by as much as 600% after they onboarded with us, as we put all of the best email marketing practices to work — proven techniques we implemented and automated to ensure the success of our clients’ campaigns. 

To give you a better idea what we mean, we’d like to give you the gift of knowledge, all contained in The Inbox Formula. 

This guidebook is a free resource compiled by our in-house email expert, and it contains a step-by-step guide to tried and tested methods that will make your deliverability grow. Moreover, the guide provides unique insight into the secrets of the email niche and shows how you can effectively run your email marketing operation yourself. 

The strategies you’ll find are the same ones we use every day, and you’ll find them smoothed out and automated as an integral part of our software. 

Sounds tempting? Grab your copy of The Inbox Formula here — completely free of charge! 

We know it works; let us know how it works for you!

Happy emailing!

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