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In Development Last updated: August 7, 2023
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Email marketing is still one of the most effective channels for reaching out to your targeted audience, who can resonate with your product or services.

According to Statista, the total number of email users globally was 3.9 billion in 2019, and this is estimated to reach 4.48 billion in 2024.

And that number is almost half of the global population.

It’s indeed fascinating!

Hence, it is a clear indication that email marketing is a great opportunity that you should not miss out on. If you have a business and, you must leverage this opportunity to reach your customers to drive traffic, enhance engagement, and boost revenue.

But you might have experienced that sometimes your email marketing efforts do not produce the desired results.

What’s the reason behind it?

Well, the reason can be many, including the quality of emails. If your email list consists of email addresses that are incorrect, have spam traps, etc., it leads to deliverability compromising.

Is there any solution?

Yes, one way to solve this issue is by using an email verification solution.

What is email verification?

Email verification involves the process of checking whether an email address is accurate, valid, and deliverable. And an email verification tool does exactly that; it is responsible for checking these aspects. The software uses techniques such as syntax check, detection of disposable address, domain check, and so on.

Why do you need it?

Marketing teams always emphasize building their email list. But chances are all those emails might not be correct.

If you keep sending emails to the wrong or invalid address, it will result in higher bounce rates. Not to mention, ISPs could begin treating your email address as Spam. Hence, all your emails will go straight to the user’s spam folders, and no one will read it, ever.

But do not worry, if you have an email verifier by your side!

Next, when you are building an email-related product or website, it is essential to integrate it with an email verifier API.

It opens a big door to possibilities, including:

Reduced bounce rates

Email verifiers show you detailed results. They can show undeliverable, incorrect, role-based addresses, so your messages land on the desired destination. With this information in your hands, you can remove unnecessary addresses to reduce bounce rates.

Clean email list

By utilizing the email API to check email addresses, you can remove invalid addresses. Hence, all you have is a clean list with only the genuine people you would love to engage with.

Improve email deliverability

When you are aware of useful email addresses on your list, you can send emails to only those users. This means the percentage of emails getting delivered into the right inbox increases. You can now compare previous results with the current result to see the improvements in email deliverability.

Cutting down cost and saves time

Storing emails and sending each one of them involves some cost and definitely time. You know how hard it is to collect that email list, maintain them, and send a personalized email to each one of them.

By filtering out emails that are not useful or incorrect, you can send emails to only genuine people. It saves your time and expenses.

Protects your reputation

As explained above, sending emails to invalid addresses for quite some time could lead ISPs and ESPs to start considering you as spam and may blacklist your domain.

This way, the sender’s reputation deteriorates. But using email verifiers, you can prevent those mishaps and continue sending messages to your targeted audience with no risk of recipients flagging your email address as spam.

Ultimately, email verifiers protect your sender reputation.

So, without doing further ado, let’s jump straight to knowing some of the best email verifier API for your products.

Abstract API

Abstract Email Verification API is a developer-focused email validation API used by over 100,000 startups and companies including Shopify, Stanford, Payoneer.

Their API checks the deliverability of an email by performing several checks and returning them in a JSON format. It includes the following.

  • Format verification
  • Typo detection with the auto-correct suggestion
  • Free email provider detection
  • Dummy email provider detection
  • Role email detection (contact, hello, team, etc)
  • Catch-all email detection
  • MX check verification
  • SMTP deliverability verification

Abstract is one of the APIs that is both GDPR and CCPA compliant by not storing any email.

You can use Abstract API for a variety of use cases including:

And many more…

They provide the largest free plan on the market with up to 500 free requests per month. Their paid plan starts at only $9 per month.


Verify whether an email address is valid or not using Hunter. It shows the deliverability of an email address with detailed validations along with a confidence score.

Hunter shows multiple levels of validations, including the format, mail server response, and domain information. It also shows a comparison with its unique base, with over 100 million professional emails. You can use the verifier to check emails in bulk, which means you can verify your entire email list.

The email checker connects directly with an SMTP server in its email validation process without sending emails to the users. Different types of verifications that Hunter performs are checking the format, gibberish, disposable, and webmail emails, MX records, accept-all domain, SMTP check, and more.

You can choose the free plan that comes with 50 requests or go for paid plans, which starts at $49/month for 1000 requests. The paid plans include full results with exports for domain search, several Gmail connections, and priority support.

Captain Verify

Verify the validity of emails easily and say goodbye to duplicates, low-quality emails, spam traps, bounces, and more with Captain Verify. It lets you import your email lists from encrypted CSV files and can analyze and audit them efficiently. 

Upon completion of email verification, you can easily download the file. Captain Verify also checks and cleans up your mailing lists easily and quickly. It leaves no room for incorrect, invalid, or misspelled NPAI emails. 

Improve your deliverability with Captain Verify’s secure service, so that you will not lose any conversation. You can also segment your mailing lists by refining all the data for better visibility.  Additionally, the solution allows you to enhance your marketing campaigns and boost your ROI. 

Captain Verify complies strictly with GDPR regulations and secures your business and customer information. In addition, it provides a precise statistical report based on the quality of your database.

Check 1000 emails at $7 by creating your account. You can also drag the slider if you want to check more emails.


Email Verification API by WhoisXML API verifies the validity, existence, and accuracy of email addresses through various real-time checks. The API has prevented more than 18+ million bounces, verified 301+ million emails, and currently monitors more than 2,000 disposable email service providers.

whoisXML API

The API runs comprehensive validation checks on any given email address, covering:

  • syntax 
  • mail server existence
  • mailbox existence 
  • email address type (generic or branded)
  • disposable email address detection
  • and more.

You may download a sample list of disposable and fake email domains powering the API in .TXT format to test this data in your environment.

Email Verification API helps users to improve their email marketing campaign results by reducing bounce rates, lessening the number of low-quality customers and leads, and preventing spam. 

Check the product sheet to learn how Email Verification API can help with your use case.


Get a 360-degree view of your emails by using ZeroBounce, which covers 30+ status & sub-status codes.

You can track the overall health associated with your email verification with a comprehensive dashboard. It provides you with reports on a daily or monthly basis where you can also select your time range to view them.

The dashboard can display four different types of detailed reports concerning individual status codes. It includes interactive graphs with points on which you can hover to get information. You can also click on a sub-status or status shown in the legend for filtering the chart and view desired data.

YouTube video

Integrating the API with your application or website is effortless. It just requires some lines of codes, and you can enjoy this lightning-fast API. You can also use their API Sandbox if you want to test your code implementations for email validation.

ZeroBounce API can easily detect and remove spam traps, abusive addresses, and misspelled domains from your email list. Hence, you can control spam complaints and protect IP reputation. It has leveraged artificial intelligence to build a scoring system that can generate quality scores of email addresses.

The API is capable of integrating with SDKs like .NET, Python, PHP, Swift, Java, and more along with different platforms like Gmail, Drip, GetResponse, Facebook, Excel, Mailchimp, Salesforce, Shopify, Slack, Magento, and many more.

For availability, it utilizes geo-redundant servers. ZeroBounce leverages anti-greylisting technology that provides accurate results. It can also identify even the gender of a few emails by looking at the first names. You can download the results if you want from the system.


DeBounce is an enterprise-grade email verifier compatible with the majority of the programming languages. This cloud-based solution is perfect for both bulk and real-time email validation.

DeBounce can take care of your email verification requirement even if you have a business with an enormous email list, or you are an individual developer wanting new users to register for your new application. They offer end-to-end services that can suit your entire need to have an email verifier. It promotes simple integration and scalability. Minimize hard bounce and invalid emails from your list using the SMTP check.

DeBounce can check catch-all domains and disposable emails. It can immediately eliminate emails with invalid syntax and duplication. It is equipped with anti-grey listing technology to reduce unknown emails.

Its intelligent indicators for spam-trap can eliminate spam records in no time. You can add your team to the DeBounce account for collaboration. You also get domain confirmation for email addresses with their status as parked, invalid, or inactive—the API checks whether the emails have valid MX records or not.

Enjoy powerful integrations with several ESPs, forms, and platforms including Hubspot, Google Sheet, ActiveCampaign, AWeber, Mailchimp, Mailgun, Drip, WordPress, CovertKit, WooCommerce, WP forms, Zapier, Stripe, Ontraport, Shopify, and many more.


Mailboxlayer is an email verification and validation JSON API. It is equipped with advanced tools like syntax and typo check, filtering disposable and free email providers, SMTP verification, checking email quality, and deliverability scores.

This tool is simple, and its URL structure is easy to integrate. It utilizes JSON format, which is again lightweight and secure through 256-bit HTTPS encryption. The moment an email lands on your systems, you can check its validity right there.

Mailboxlayer is linked with multiple databases that are updated regularly and contain email providers, separating disposable and free emails from individual domains. The API has typo checks, reflects numeric scores, and provides did-you-mean suggestions to show email quality. This way, you can filter genuine emails from abusers.

Mailboxlayer API facilitates JSONP callbacks and offers JSON formatting to increase email readability. It displays quality scores from 0 and 1; 0 is for bad, and 1 is for good. It reflects the email address quality and deliverability.

Email Hippo

With Email Hippo, you can validate email addresses in your list quickly while analyzing 74 data-points for each one of them. It is a perfect option to integrate it into your email-related products because it produces real-time results and generates a unique trust score – Email Hippo Trust Score.

You can use it to filter online signups, refreshing databases, and cleaning your CRM systems. Get better control of your email list by finding “catch-all” emails that have low opening rates.

Protect sender reputation by removing emails that are blacklisted for spamming. This email verifier can also identify domains charging gatekeeper fees in order for emails to reach the desired destination. It helps you segment your data better by giving you information about the concerned mail system so you can improve deliverability and engagement.

Email Hippo can detect role-based emails that generally have low open rates as compared to named addresses. It also checks MX records to increase the scope for email deliverability along with greylist and gibberish email detection.

You can even detect domains with dark web links using Hippo. Locate mail servers to filter out fraudsters and scrutinizing sales leads. You get a comprehensive dashboard with reporting tools and user-defined layouts along with detection summaries that can be downloaded.

Email Hippo delivers results from multiple data points and helps you create workflows effectively. It also checks syntax errors in real-time, helping you to create and send alert responses. What’s more – you can also identify whether an email address is private or business email, which comes handy for your marketing efforts.


Enjoy better delivery rates by using the real-time API – SendGrid to identify and remove invalid emails. It is powered by machine learning and tactics that are friendly to mailbox providers for boosting delivery.

SendGrid can identify mistyped, disposable, inactive, non-existent, or shared emails. By connecting the API to your lead capture forms, you can detect false entries straight away. You can also prompt visitors to re-submitting the forms in accordance with the correction suggestion without extra fields for confirmation.

SendGrid does not utilize broken SMTP-handshake, which is a spamming tactic that many vendors use to validate email addresses. They maintain the trust of mailbox providers by facilitating only the whitehat senders.

Their machine learning algorithms inform the validity scores of email addresses so you can detect which ones fall in the “good email” category. The ML model they use is trained with 60 billion email data per month and is maintained and crafted by their data scientists. Additionally, they protect your data by complying with GDPR.

SendGrid also has email templates having conditional formatting and HTML rendering. It also provides SMTP service and lets you test performance against spam, inbox rendering, and link validity.


Mailgun performs 3-step validation checks for your email addresses. It includes checking the email against its mailbox provider. It also validates emails in custom grammar set forth by the ESPs. Mailgun integrates grammar checks with Gmail, Yahoo, Hotmail, etc. into the email validator.

With Mailgun, you get a stronger sender score, so your domain names and IP addresses have a positive reputation. It can also catch errors and detect bad addresses to eliminate the chances of delivery issues. Once you integrate the API into your sign-up forms, it can start cleaning your email list.

You can expect reduced bounce rates as the verifier removes spelling mistakes, disposable emails, and temporary addresses. It is capable of validating over 200 million addresses a month. It performs mailbox verification to confirm whether the mailbox exists or not on the targeted domain.

You get a reporting dashboard to track validations according to an hour and day while finding specific data regarding email addresses and API call types. You can enable rate limits for API key validation to prevent abuse and manage costs.

Apart from that, you can check roll-based checks and disposable mailboxes as well. Mailgun provides log retention for up to 30 days with complete details on sent emails. Get advanced email analytics to measure your marketing efforts.


Using Trumail for email verification is straightforward. You just need to execute a GET request. As of now, it supports three formats – JSON, XML, and JSONP with a callback query parameter.

The API is written in Go and was built keeping in mind to provide an easy to use and simple solution to developers and businesses. All can leverage the email verification API to filter their email list and reap its holistic benefits.

Make better decisions as to whom you must send an email to with the help of its accurate and real-time results. To get started, just enter the email address you want to check, hit the button next to it, and wait.


Reacher is an open-source email verification API. It is written in the performant language Rust, which makes it fast: it currently takes 1.9 seconds on average to run a real-time email verification.

The API comes with decent documentation. However, you can also try Reacher’s JavaScript SDK for bulk validation. Reacher’s business model is a SaaS subscription offering, but since it’s open-source, there is also a possibility to self-host the service yourself.

For personal use, Reacher offers 50 free email verifications per month.


Email marketing is evergreen, and to continue leveraging the most of it, you must have a clean email list with fewer or no invalid or spam emails. Use any of the above-mentioned verification API to integrate with your products for better deliverability.

  • Durga Prasad Acharya
    Durga Prasad Acharya is a Freelance Technical Writer who loves writing on emerging technologies, such as AI & ML, Cybersecurity, Web Hosting, SaaS, Cloud Computing, and more. Besides writing, he’s a web designer and is passionate about… read more
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