How to Check If an Email is Valid

What is email validation?

Email validationⓘ is a process used to check if an email address is real, in use, and deliverable. The validation tool checks for valid syntax, a valid domain and username, and that the address is configured to receive incoming emails.

Email validation differs from email verification. However, both terms are commonly used interchangeably as both processes work together to ensure that an email address is deliverable.

• Validation – Investigates the syntax and structure of the email address (e.g., follows the format username@domain.com)
• Verification – Uses different rules and techniques, such as SMTP pinging, to confirm that the mailbox exists and is active

An email validation service will often combine both terms under the umbrella of "email validation" as both techniques are required to check if an email is valid.

Why email validation matters

Without a method to check if an email is valid, your email list will inevitably populate with fake, invalid, expired, and bot-generated email addresses. When you send email campaigns to invalid addresses, your communications don't reach the inbox.

Here are a few reasons why your email list often contains invalid data.

People change email addresses

Do you still use the same email address you had years ago?

Email users frequently change their mailboxes for various reasons. Our latest study found that 28% of the average email list decays annually. Here's why:

• The contact left their job or the company
• The contact received a promotion or position change and received a new address/mailbox
• Company layoffs
• Issues with spam emails or phishing attempts
• Privacy concerns

A once-valid email address can become invalid without warning. Without an email validation tool, your email bounce rate increases, your engagement declines, and your revenue suffers. Your emails stop reaching actual contacts.

Disposable and bot-generated email addresses

Your visitors won't always use their actual email address when signing up on your forms. Thanks to scraping tools, bots, and malicious actors, internet users are increasingly skeptical about sharing their email addresses, particularly their business addresses.

Sites like TempMail allow anyone to create a fake disposable email address. They're valid for fifteen minutes before expiring and becoming invalid.

Spam traps

There are a variety of harmful email addresses that you need to avoid, but spam traps can destroy your business's sender reputation.

Spam prevention services often create spam traps, also known as "honeypots," and feed them into mass email lists to catch spammers in the act. However, it also puts mass senders like you, who aren't using email validation services, at risk of deliverability problems.

If you're a bulk email sender (someone who sends 5,000+ emails per day), you're on the hook by internet service providers (ISPs) to follow certain guidelines.

The key rule regarding email validationⓘ is to maintain an email bounce rateⓘ of 2% or lower.

If you don't know how to check if an email is valid, you'll encounter invalid email addresses, spam traps, and other high-risk emails in a matter of time.

Fortunately, email validationⓘ is made simple by using dedicated email validationⓘ services.

How to check if an email is valid (4 methods)

There are various ways to check if an email is valid, but only a few are reliable and safe. Here are some recommendations along with the potential drawbacks.

1. Use an email validation service

You can check if an email is valid by using email validationⓘ software in the following three steps:

1. Visit an email validationⓘ service like ZeroBounce. You can check if an email is valid by using a tool like the free email verifier.
2. Enter the email address and click 'Verify'

3. The email validator returns a result that shows the "status" of the email address as either "valid" or "invalid." The sub-status may display additional information, where possible, regarding the nature of the email address.

There are additional email validationⓘ techniques recommended for businesses and bulk email senders: bulk email validationⓘ and real-time email validationⓘ via an API.

Here's how to check your email addresses with those methods.

How to validate emails in bulk

1. Find an email validationⓘ service that supports bulk email checking.
2. Upload your email list as a file. From your Email Service Provider (ESP) or Customer Relationship Management (CRM) tool, export your email list. Your file should be a CSV, TXT, XLS, or XLSX file.

3. After uploading the file, confirm that all values found by the service match what's in your file. Proceed.
4. The email validationⓘ tool will check all email addresses in the file. ZeroBounce currently validates approximately 100,000 email addresses in under thirty minutes.
5. Download your results file. The file will include subfolders that separate each email address on your list by their validation status. You can upload your list of "valid" emails back to your ESP or CRM.

How to validate emails in real-time

To check if an email address is valid in real time on your website forms, complete the following steps:

1. Obtain a real-time email validationⓘ API from an email validationⓘ service. This API enables you to integrate the platform into your website or landing page.

2. Retrieve your account API key. If using an email validationⓘ service like ZeroBounce, you can find your API key within your account settings.

3. Add the API code to the backend of your website alongside your signup form.

If you lack programming experience or don't have access to the website backend, you can simplify the process by using a dedicated tool like ZeroBounce's JavaScript Widget. This acts as a "plug-and-play" solution to check if an email address is valid as the visitor enters it into your signup form.

These aren't the only ways to check if an email is valid. There are various techniques and tools available, including dedicated JavaScript libraries and basic regular expression checkers. However, these methods aren't preferred as they suffer from accuracy or volume limitations, and won't provide long-term, reliable results for mass senders.

There are other ways to check if an email address is valid, but some of these options may have drawbacks you'll want to avoid.

2. Send an email to the address

Sending an email to the address is the most direct method of email validationⓘ. If the email is delivered, it's valid. If not, your message will bounce back with a message from your ESP.

Here's the problem: a high bounce rate hurts your sender reputation. While a one-off bounce isn't a big deal, if you're a sales rep or a marketer looking to reach out to a bigger list of emails, you can't afford to bounce so many messages.

Furthermore, manually emailing a large list is time-consuming and impractical.

3. Performing a web search

To check if an email is valid, search the web and qualify the results. For example, if you're looking for an executive at Company A, their email address may appear in search results for their company website or other related URLs.

If you choose this method, investigate when the website was last updated. You might also follow through and look for their LinkedIn profile to verify that they're still at the company.

Overall, this method isn't recommended as there is no way to guarantee that the email address is valid and accurate.

4. Using a regex checker

You can check if an email is valid by using a regular expression (RegEx) check on your website forms. An email regex contains a string of permissible characters, compares that to the characters entered by the user, and returns a result.

Email RegEx checks are vital for email validationⓘ and are included in every email validationⓘ tool or software. The issue is that a RegEx check alone doesn't verify that the mailbox actually exists or is configured to receive incoming messages.

While it's recommended to protect your forms with a RegEx checker at a minimum, you're better off using a dedicated email validationⓘ API that provides both RegEx checks alongside additional, more sophisticated validation methods.

How does email validation work?

Email validationⓘ works by performing a series of checks, including the following:

1. Syntax check – This initial step verifies that the address uses a valid format (e.g., username@domain.com) and is free of potential typos.
2. DNS record check – This step checks that the email address is configured to receive incoming mail and contains valid MX (mail exchange) or A-type DNS records.
3. Spam trap check – The email validation tool checks the address for any known spam signatures and filters out anything detected as a potential spam trap.
4. SMTP check – The SMTP check, also known as mailbox pinging, is a test that confirms whether the address can receive emails. Think of it like calling a phone number, waiting for it to ring, and then hanging up.
5. Validation results and rechecks – At the final stage, the email validation tool will determine if an email address is "valid," "invalid," or some other high-risk email type. Any email addresses with an undetermined status may be re-validated by the tool to circumvent common roadblocks such as greylisting.

Accurate and dependable email validationⓘ is a technical process that not only includes these steps but may also include proprietary processes to detect better a wider range of email address types, including "disabled" mailboxes, "toxic domains," and other email addresses that can pose a risk to your deliverability.

When to validate emails

You should check if an email is valid any time you add a new contact or address to your email list or CRM. Proactive email validationⓘ helps avoid bounced emails, missed communications, and keeps your database clean and up-to-date.

Here are some additional guidelines and recommendations to help you with email validationⓘ timing:

• Validate every new email address or list before adding it to your database.
• At a minimum, clean your database with an email validation once per quarter.
• Consider checking your email list more frequently, depending on your list growth rate and latest campaign performance.
• Add a real-time email validation method to your signup forms to check if email addresses are valid automatically.

If you're sending emails from your personal address to friends and family, email validationⓘ isn't a requirement. However, know that emailing an invalid email address will cause the message to bounce.

Anyone involved in business outreach, including marketing, PR, sales, or business development, must check if an email is valid – every time.