What is a valid email address format

In this article, we will explore the factors that determine the validity of an email address and how to check if an email is valid.


What makes an email address valid:

How to check if an email address is valid:

The importance of having valid email addresses

The fundamental principle of email marketing is to send email drip campaigns to valid email addresses because achieving good results is only possible when you actually reach the inbox and engage with potential customers.

Keeping your email list valid and clean helps minimize the number of bounces you get, improve your sender reputation and deliverability.

Ultimately, with accurate email contact information you generate more leads and increase the chances of converting them into customers.

What makes an email address valid

But what determines the validity of an email? Let’s dig deeper into the factors that define a valid email address.

Factor #1: Email address format

A valid email address consists of two main components: the username and the domain name.

Username (before @) identifies the email address user with a unique name. Domain name (after @) represents the email provider or organization hosting the email account.

So, a valid email address follows the format: username@domain.com. However, there are specific requirements for acceptable usernames and domain formats.


Component Syntax requirements Valid email format examples
Username Allowed characters:

  • latin letters (a-z).
  • numbers (0-9).
  • special characters: underscores (_), periods (.), and dashes (-).

A period (.) is not permitted at the start or end.

Consecutive periods or special characters (e.g., john…doe@company.com) are not allowed.

Special characters should be followed by one or more letters or numbers.






Domain name Consists of one or more parts separated by a dot.

The second part must be at least two characters, for example: .com, .org, .cc

Allowed characters:

  • latin letters (a-z)
  • numbers (0-9)
  • dashes (-), excluding the use of dashes at the beginning or end.






Factor #2: Email address authentication

Not all email addresses that are correctly formatted are automatically considered valid. The most important factor is that the email address actually exists and is active on the mail server.

This is confirmed through authentication, a process that ensures the email address is legitimate and verifies its existence on the mail server.

It involves checking the email address by verifying its domain through MX records and authenticating the email account using SMTP server commands to confirm its active status and ability to receive emails.

How to check if an email address is valid

There are few methods to check the validity of an email depending on the number of emails you need to verify.

Method 1: Single Email Verification

This method is suitable for you if you only need to verify one or a few emails.

  • Send a test email manually:

You can verify an email by sending a message to it from your email client and checking if it bounces back or delivered successfully.

You can enter an email address into the verification form and see its status without the need to manually send an email. This method prevents any potential harm to your sender reputation.

Method 2: Bulk Email Verification

This method lets you to check multiple emails at once or verify a large number of emails by uploading a list.

Our bulk email verifier can help you run verification checks on your entire email list in bulk and remove any invalid addresses from your list.

Use bulk email verifier ⇒

It includes syntax checks, MX record checks, SMTP authentication, and other tests for maximum verification accuracy.

Learn more in our guide on how to verify a list of email addresses with Snov.io.

Read next:

If you’re facing high bounce rates and poor lead quality, we have a solution for you outlined in our Sales Cheats resource – a complete roadmap on how to fix the most common problems in the sales process and improve your outreach results.

Learn how to prevent high bounce rate ⇒

You can also collect pre-verified emails with Snov.io. Most of our email finder tools come with a built-in verifier.

Learn more about our prospecting tools ⇒

Once you have a list of valid emails, you can create a personalized automated sequence to reach your potential clients.

Read guide on how to launch your campaign step by step ⇒

Was this helpful?

Thanks for your feedback!

Sorry about that 😢

How can we improve it?

Snov.io Academy: From Lead Generation to Closing Deals

Are you getting the most out of Snov.io? Learn prospecting techniques and outreach strategies that result in more sales with minimum input.