Last updated
August 3, 2023

Bulk Email Validation

Elizabeth (Lizzie) Shipton

Table of Contents:

Get your free
Email Validation
API key now
4.8 from 1,863 votes
See why the best developers build on Abstract
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.
No credit card required

Email addresses are a critical part of a progressive web app or mobile app. They are also important for websites that collect information for business leads or a newsletter through a simple contact form. Email marketing campaigns are still the most effective form of online marketing.

Whatever your end goal when collecting user email addresses, be it lead generation, user authentication, or something else, verifications and validation must be performed on every email address a user enters into your site.

But what happens in the case that you need to validate or verify email addresses in bulk? For example, say you have a lot of unvalidated email addresses in your database already, or you receive a lead sheet or mailing list with a lot of unvalidated email addresses. Best practice dictates that you should go back and validate those email addresses using an email verifier.

In this case, you are going to need a bulk email validation tool to help you. In this article, we'll take a look at some of the best bulk email verification and validation tools, and how you can use them to weed out invalid email addresses from large datasets.

Let’s send your first free
Email Validation
See why the best developers build on Abstract
Get your free api

What Is Bulk Email Verification?

Bulk email verification is different from the regular email validation or verification process because it typically doesn't require any input from users. It's unlikely you'll ever need a frontend to allow users to enter email addresses in bulk unless you are building your own bulk email validator.

Usually, when you verify multiple email addresses, it's through the use of a CSV upload or a script that runs against all of the email addresses in your database. In this article, we'll focus on some service providers that validate bulk email addresses through use of a file upload.

After you upload your CSV or another file, the bulk email verifier runs each address through a validator that checks for the following things:

Let's take a quick look at each of these validations in depth.

Email Address Syntax Errors

This step is fairly obvious. Check for any improperly formatted email addresses (i.e., addresses that contain unexpected characters or non-existent domains, etc.) Email addresses are usually validated against a standard like the IEFT Standard. This step might be performed using a very complex Regular Expression.

Validating Domain MX Records

This step looks up the DNS records for an email's domain. When a domain gets set up to deliver email addresses, certain DNS records must be created in that domain to ensure deliverability.

Usually, a domain must have at least a domain MX record and often an SPF record. If the domain is found to be invalid, or the records are missing, the email addresses from this domain are considered invalid email addresses.

Disposable Email Address (DEA) Detection

Disposable emails are temporary email addresses that people use to bypass sign up and login forms without providing their real email addresses. Needless to say, you don't want these "junk collector" email addresses on our mailing list of email addresses, so they should be removed.

Role-Based Account Detection

Email addresses that start with admin@, info@, sales@ or staff@ can hurt your reputation with email service providers and lower your deliverability score. If these types of email addresses are present in your list of email addresses, you certainly want to get rid of them.

Honeypot / Spam Trap Detection

Spam Traps are used by email service providers to detect spam email addresses and reject them. If your database or mailing list contains spam email addresses, you should purge them from the list as soon as possible.

Extended SMTP Validation

A deep-level SMTP verification is the process of pinging each email address on the list of bulk email addresses to validate that the mail server has a mailbox for this address. It does not actually deliver an email to the address.


A DNS-based blackhole list (DNSBL) or Real-time Blackhole List (RBL) is a list of IP addresses often used for spamming. The process of checking for DNS-based blackholes involves checking emails and IP addresses against known DNSBLs and URI DNSBLs to weed out spam networks.

When Should You Do Bulk Email Verification?

If you run a mailing list or newsletter or maintain a list of email addresses for lead generation or some other purpose, it's important to do regular list cleaning. If you're paying to send out email marketing campaigns through a service like Mailerlite or Mailchimp, you don't want to pay to send emails to invalid email addresses.

A good cadence for performing bulk email verification is to clean your list at least once every six months. This should purge your email list of any invalid, spam, or undeliverable addresses. At the same time, you should also make an effort to re-engage or dump inactive subscribers (i.e. users who receive your emails but never open them or click on anything.)

Some Bulk Email Verification Services

There are many bulk email verification tools out there that can quickly and effectively purge your email list of invalid email addresses for a price. There are also several free bulk email verification tools that are excellent options too. Let's compare some of the top options, and learn how to use the AbstractAPI Free Bulk Email Verifier to clean up a bulk email list.

Paid Bulk Email Verification Tools


ZeroBounce is an award-winning bulk email verifier that lowers the bounce rate of high-volume emails by checking for invalid email addresses, validating IP addresses, and verifying key recipient demographics.

ZeroBounce has no free bulk email verification option, and the cost to validate email addresses is quite high. The basic plan starts at $16 to validate 2000 email addresses. From there, bulk email verification plans start at $390 for 100,000 emails and run up to $2250 for 1 million email validations.


MillionVerifier is a slightly less-expensive option than ZeroBounce. The tool has a 99% email verification accuracy rating and guarantees a less than 1% bounce rate. Having a low bounce rate improves your sender's reputation and leads to a greater open rate and deliverability.

MillionVerifier plans start at $29 for 10,000 emails verified, then increases steadily. The cost to verify 1 million emails is $299. As you can see, the rate is significantly lower than ZeroBounce, and you will only ever be charged for emails that were successfully verified. They offer a free trial of 100 free credits.


MyEmailVerifier offers a flexible pay-as-you-go plan, so there are no up-front costs. The company has a 98% accuracy rate and guarantees a 2% bounce rate. They offer discounts to non-profits and educational companies. They are also the only service that claims to be able to detect "disabled users" in Yahoo and AOL.

MyEmailVerifier plans start at $1.44 for 500 emails. The cost to validate 10,000 emails is $21.60, and the cost for 1 million emails is $289, which is the lowest price of any of the paid tools on this list. They offer a free trial of 100 free credits.

Best Free Bulk Email Verification Service

In addition to the paid email verification tools out there, there are a number of free bulk email verifier options available too. These tools are perfect for businesses just starting out or for those who don't have a lot to spend on maintaining their email list.

AbstractAPI Free Email Verification API

AbstractAPI has a free email verification and validation API that offers a bulk email upload option that can process a CSV of bulk email addresses. The API performs checks for syntax errors and formatting, as well as free and disposable email address detection, deep SMTP checks, Domain MX records lookups, and a deliverability value and quality score for each email address.

The free bulk email plan allows you 100 API calls per month, which can be used either for bulk email verification or to validate single emails from a frontend application or other client via an AJAX request.

AbstractAPI also offers paid tiers for its email verification tools, both the bulk email uploader and the validation API. Plans are based on a monthly subscription and start at $9/month for 5000 API requests. The next tier is $49/month for 50,000 API requests and then $99/month for 100,000 API requests.

Bulk Email Validation With AbstractAPI

Let's look quickly at how the bulk email validation process works with AbstractAPI's free bulk email verifier.

Get Started With the API

In order to use the API, you'll need an API key to authenticate. Navigate to the API homepage and click on the blue "Get Started" button.

If you've never used AbstractAPI before, you'll be asked to create an account using your email address and a password. If you have used the service before, you may need to log in.

Once you've logged in, you'll land on the API dashboard where you'll see links to documentation and pricing, as well as your unique API key. AbstractAPI keys are unique to each API, so even if you have an API key for a different AbstractAPI endpoint, you won't be able to use it to authenticate with the email validation API.

In the list of links on the left side, you'll see an option for "Bulk upload (CSV.)" Click that to be taken to the bulk upload page.

Click the blue "Upload CSV" button on the right. A dialogue box will open with a file browser in it.

Use the file browser to select the CSV file that contains your bulk email addresses and click "Upload CSV." Depending on the size of your file, you'll see a loading indicator while the upload processes, and then you should see a success dialogue box telling you that the file was received and that results will be emailed to the address from your AbstractAPI account.

Check your email for the results. If the file is quite small, you should receive the email almost instantaneously. For larger files, it may take a few minutes.

Inside the email, you'll see a button to download the resulting CSV file. You will also be provided with a link to a hosted version of the file. This is handy if you need to share results with a number of team members.

The file can be opened in any spreadsheet program, including Apple Numbers, Excel, or Google Sheets. It will contain the same information you would receive from the API as a JSON object when making an email validation request via the endpoint.

You will see a quality score and values that indicate whether the address is formatted correctly, deliverable, whether it is a free email, a disposable email, a role-based account, a catchall email, or whether domain MX records were found, and whether the SMTP is valid.

From here, you can use the filtering options within your spreadsheet software to purge the invalid email addresses from the bulk email list. If the list is very long, you could also write a script to iterate through all the values and remove invalid email addresses.


Bulk email verification is an important part of maintaining an active and healthy email list. Attempting to deliver to invalid email addresses hurts your reputation as a sender and can affect the delivery to the legitimate emails on your list.

Furthermore, if you pay for a service like Mailchimp to run email campaigns or other marketing campaigns, you don't want to pay for that service to deliver to addresses that don't exist or don't have value.

Regular list cleaning and purging are important. If possible, try to use a bulk email verifier to clean your email list at least once every six months. At the same time, you should also run re-engagement campaigns for inactive users who no longer open your emails.

A tool like AbstractAPI's Free Bulk Email Verifier can be incredibly useful when it comes to removing invalid email addresses from your list. In addition to this free bulk email verifier, there are many paid options including the ZeroBounce bulk email verifier, the MillionVerifier bulk email verifier, and MyEmailVerifier bulk email verifier.


How do I verify bulk email addresses?

The easiest way to verify emails in bulk is to use a bulk email verifier or verification services like AbstractAPI's Free Bulk Email Verification API, ZeroBounce, or MillionViewer. These bulk email verifiers allow you to upload a CSV containing a list of your email addresses to be validated.

A bulk email verification tool runs several checks against the emails in your list of email addresses. The bulk email checker will look for improperly formatted addresses, known spam traps, free and disposable emails, invalid MX records, invalid domains, and role-based email addresses. It will also run a deep-level SMTP check.

How can I bulk verify my emails for free?

One of the best free bulk email verification tools is the AbstractAPI email verification tool. This is an API endpoint that accepts email validation requests via AJAx. However, there is also a bulk verification option that allows you to upload a CSV file of email addresses.

The API runs validation checks against all the emails in the list and then emails the results to you in a CSV file that can be opened with any spreadsheet tool like Google Sheets or Excel.

How Do I Check if an Email is Valid?

There are many ways to determine whether or not an email is valid. First, the email must be properly formatted (i.e. no syntax errors or typos.) Next, it must come from a valid domain and have proper MX and SPF records. The email must not be from a service that provides temporary or disposable emails, and it must not come from a known spammer.

A good email verification tool will run several checks against an email to determine whether or not that email is valid.

Elizabeth (Lizzie) Shipton
Get your free
Email Validation
key now
This is some text inside of a div block.
get started for free

Related Articles

Get your free
key now
Email Validation
4.8 from 1,863 votes
See why the best developers build on Abstract
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.
No credit card required