How To
Feb 2, 2023

The Easy Way to Build a Valid Email Address List

According to a report, more than 20% of emails either reach the spam folder or remain undelivered. If you are an email marketer, this is a worrying stat, as low deliverability equals poor ROI of your email marketing campaign. Many factors affect emails' deliverability, but the biggest is email validity.

Valid Email addresses have a pretty specific format and there isn't really any wiggle room:

  • The prefix appears to the left of the @ symbol
  • The domain appears to the right of the @ symbol

And there can't be any spaces in between!

For example, in the address "info" is the prefix and "" is the email domain.

When email lists with wrong addresses, burner emails, and fake domains are common, you must perform email validation before hitting send. So, let's look at some convenient means to detect valid and invalid emails so your emails always end up in the recipient's inbox.

Of course, one method that we are exited about are Gigasheet's built-in email verification tools!

Valid Emails Explained

Before diving into the details, let's first define a "valid" email address. A valid email address follows the syntax and standards set by the Internet Engineering Task Force (IETF). Criteria include rules for the format of the email address, as well as the domain name and top-level domain (TLD).

Reasons to Validate Email Addresses

You should regularly perform email validation to reduce the chances of landing in the recipient's spam folder. But it also brings the following benefits for marketers:

1. Deliverability

Invalid email addresses result in bounced or undeliverable emails, lowering your sender's reputation and deliverability. By validating email addresses, you ensure that your emails are delivered to the right people.

2. Accurate Email List

Email validation helps ensure that your email list is accurate and up-to-date. This is especially important if you have an extensive email list that you want to keep clean and organized.

3. Spam Complaints

Sending emails to invalid or inactive email addresses results in a high number of spam complaints, which, not to mention, harms your sender's reputation. Email address validation can prevent spam complaints and improve the chances of your emails being delivered to the recipient's inbox.

Easiest Ways to Build a Valid Email Address List

Now let us have a look at some easiest ways you can validate your email list:

1. Online Email Validation Tools

One of the simplest ways to validate email addresses is by using an online email validation tool. A simple Google search with the keyword "online email validator" will bring up many tools to enter the email address and check its syntax, domain name, and mail server. Some tools even go a step further and check for temporary or disposable email addresses, often used to bypass spam filters or hide a user's identity.

But online email address validation tools have their caveats. For one, they limit the number of emails you can check so often, allowing users to check only one email at a time. Second, these email validation tools provide basic validation, and you must pay for extra features and searches.

2. Pass a Regex in Python

If you know the basics of programming, you can use a regular expression (regex) in Python to check the syntax of the email address for email data validation.

As you know, an email address is a unique string of characters, including letters and digits. A regex is a sequence of characters that you can use to search for patterns and check the syntax of an email address.

For example, you use the following regex to validate if an email contains "@" that is preceded and followed by one or more non-whitespace characters:


However, if you were to perform more extensive email data validation, you would have to use more complex regex. Or you will need to write an if-else code in Python, which is not everyone's cup of tea.

Here is a Python code snippet to check validity of emails:

Python code snippet to build a valid email address list

Use Gigasheet's Email Enrichment for Email Address Validation

When you say the easiest way to detect valid and invalid emails, you do not mean a way with limitations email checks, and definitely not one that needs extensive coding. That is why we created Gigasheet, a no-code data analytics tool, and added one-click email enrichment to it.

Gigasheet uses Abstract API's Email Verification and Validation API to enable email enrichments. You need to have an account with Abstract API, and you can just enter the API code to authorize Gigasheet to perform email validation.

Let us walk you through the Gigasheet's email address validation process step by step:

Step 1: Get Your Abstract API Key

Abstract API's Email Verification and Validation API is the world's leading API allowing users to benchmark their email list against an extensive record of email addresses and domains. Just Visit and create a free account. You get 100 requests free of cost each month. So, feel free to experiment before upgrading to paid tiers. To find your private API key, go to the Try it Out tab and copy it.

Snapshot of Abstract API's Email Verification and Validation API webpage.

Step 2: Get Started with Gigasheet

Next, head over to and sign up for free. You can also use your Google, Microsoft, and GitHub ID for seamless login.

After logging in, click on New and upload your email list. You can upload files in all popular formats, including JSON, CSV, XLSX, and more. Once the upload is complete, click on your file, and Gigasheet will process it in spreadsheet format, which is easier to work it.

Drag and drop files to upload them to Gigasheet.

Step 3: Use Gigasheet's Data Enrichment for Email Address Validation

To begin email address validation, click on Insert and select Enrichments from the options.

Sample email list opened in Gigasheet.

Now you will see a Data Enrichment pop-up. Just select the email column and tick the checkbox for Email Validation. Then, paste the Abstract API key you copied earlier, click Apply, and sit back.

Snapshot of data enrichment pop-up window in Gigasheet.

Step 4: Results of Gigasheet Email Validation

Gigasheet may take a minute or so to complete its email data enrichment process. Once done, you will see two new columns:

  • The Deliverability column shows the deliverability of an email address with the following values: DELIVERABLE, UNDELIVERABLE, RISKY, and UNKNOWN.
  • The Quality Score column contains the Abstract's evaluation for an email address shown as a decimal score between 0.01 and 0.99.
Email enrichment generates two new columns - Deliverability and Quality Score.

Step 5: Analyze Your Email List

Once your deliverability and quality score for your email list, you can dive further into email validation. You can sort and group columns, create groups within groups and apply filters for easy analysis.

Here we have grouped rows by column Delivery which gives the following result:

Email list filtered by column Deliverability.

Final Thoughts on Valid Email Address List Building

Using Gigasheet's data enrichment feature for email validation easily surpasses other methods of validating email addresses. Just upload your email list, apply enrichment, and there you have valid and invalid emails. You can even use filters and group rows to analyze your email list further to reveal any underlying patterns. With Gigasheet, improving your email list's deliverability is just a matter of a few clicks, and it is free to use.

Sign up for free to try it today!

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