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Top 6 Best Email Lookup APIs

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Top 6 Best Email Lookup APIs

For many organizations, a quality, active email list is the lifeblood of your sales and marketing efforts. Sending to undeliverable, unknown, or invalid addresses can not only decrease your campaign effectiveness, but it can ruin your sender reputation. That’s why Email lookup APIs are important.

In this post, we will take a deep dive into the world of Email Lookup APIs, and give you our 6 best choices to date.

What are Email Lookup APIs?

Wouldn’t it be nice if you could know if an email was valid before sending an email? Or even better – if you could find emails by only knowing the domain. Well, that’s exactly what an email lookup API does.

Benefits of Using Email Lookup APIs

By using an Email Lookup API, you get to eliminate hours of hunting for email addresses and get in contact with the right people, quicker. It’s also traditionally more affordable than buying marketing lists, which can be unreliable and out of date.

Different Types of Email Lookup APIs

There are all different types of email lookup APIs. Some serve as validation tools that help validate syntax, while others verify deliverability, domain, read reputation, and even enrich emails with additional attributes, like company name, website, contact, or social media account information.

So, what Email Lookup API is right for you? Let’s dive into our choices for the Best Email Lookup APIs.

Best Email Lookup APIs

1. Best for small or large enterprise sales teams email finder helps sales teams and marketers find professional emails. Launched in 2015, lets you get to the decision-maker, faster.


  • Flexible API makes it easy to search and verify emails.
  • Intuitive and lightweight web-based, is easy to use.
  • Built-in marketing capabilities like campaigns and leads.


  • Although it’s worth it, it can be pricy for smaller, enterprise teams.


As of this article, here is the pricing breakdown for You can also sign up for a free account.

  • Starter – $49/mo
  • Growth -$149/mo
  • Business – $499/mo

2. Clearbit: Best for organizations that have a sophisticated inbound strategy


Clearbit is a soup-to-nuts outreach platform that helps you identify site visitors, capture leads, and build a qualified pipeline. Unlike, Clearbit manages a massive dataset of contact and company information that pulls from multiple sources, so you don’t have to go hunting for emails.

With Clearbit, you can set your ideal customer profile and let the suggestions roll in. Using the Chrome Extension, you can navigate to a website and instantly see relevant information about a company and the people associated with it.

You’re also able to run visitor reports on your website by installing a script to automatically pull contact information from your visitors.


  • TAM Calculator- View and calculate the Total Addressable Market for and search for your ideal customers
  • Connect – As you browse the internet for prospects, connect will reveal relevant company and personal contact information for that person or domain. From here you can view emails and automatically add them to your CRM.
  • Segmentation and Targeting- You can target and send personalized ads to prospects by leveraging Clearbit’s massive database.


  • The Chrome Extension is really powerful. You’re able to tap into contact and company information easily while navigating any website.
  • Track detailed visitor information on your website.


  • More complex than other tools, especially to set up visitor tracking scripts.
  • Doesn’t provide one-off email validation or verification tools, which can be helpful with prospecting.


As of this post, Clearbit provides free and paid versions. The paid version is a consultative sale based on your organization’s needs.

3. AbstractAPI: Technically savvy teams that are looking for the flexibility to leverage different email APIs

AbstractAPI email validation API

AbstractAPI provides a large library of powerful API’s different use cases, including email verification and validation. With the Email Verification API, you can check the verification status of domains to improve contact quality and deliverability rate before you launch that campaign.

It’s pretty easy to use. Just use their provided API key and helpful documentation and make a request.

With AbstractAPI, you can also enrich existing company data through the Company Enrichment API endpoint and get company information from any domain.

In addition to Email Verification, AbstractAPI provides phone verification, web scraping API endpoint, stock market, and translation APIs.


  • Generous free versions with plenty of API calls
  • Wide range of API selections with dozens of use cases


  • Doesn’t include an email finder API to locate email addresses and can only verify them
  • More technical than and other similar tools.


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4. VoilaNorbert: Teams looking for prebuilt integrations with other popular technologies


VoilaNorbert claims that they’ve helped their customers find over one billion emails. Now, that’s a lot. With an easy-to-use email finder, verification tool, and email enrichment, VoilaNorbert is a great Email Finder API. Like some other tools on this list, you’re able to use a manual search, bulk uploads, or an API.


  • Email Finder – Easily search by name or domain to find accurate and deliverable email addresses of key decision-makers.
  • Verify – Upload a list of emails and have VoilaNorbert quickly verify with 98% deliverability, saving time, money, and sender reputation.
  • Data Enrichment – Upload a list of emails and return enriched, additional data like social media profiles, websites, and other available information.


  • Quick and easy to use.
  • Flexible pricing options, including monthly subscription or per-use pricing
  • Neat, unique features like email deduplication and native easy-to-setup integrations with Salesforce, Zapier, and many other tools.


  • Reviews often site a more robust feature set would be nice
  • “Touchy” chrome extension.


As of this writing, VoilaNorbert offers four different types of pricing options as well as the ability to purchase one-off bulk verifications and lookups. You can also sign up for a free account.


5. Solopreneurs and small businesses all the way to large enterprises is an impressive email finder and marketing tool that’s great for solopreneurs and small businesses all the way to large enterprises. It has a comprehensive offering that goes beyond the traditional email finder API, lookup, domain search, and verification APIs – like email campaigns and a lightweight CRM.

You can use to not just find verifiable emails but to also automate drip campaigns, and warm outreach. You can even connect with existing email databases to enrich and forms to automate email messaging.

By upgrading to a paid subscription, you get an API key and access to helpful API documentation.


  • Warm Up – Just because you send an email to the right address, it doesn’t guarantee your prospect will receive it. can create an AI-based warm-up strategy to make sure your emails land in your prospect’s inbox.
  • Social URL Search – Upload a CSV of your prospect’s LinkedIn URL and can help locate an email.
  • Database Search – Leverage the database to search based on a variety of criteria like job title and location.


  • Offers a ton of features.
  • Easy to use and intuitive UI.
  • Ability to leverage an existing database of prospect emails.


  • So many different ways to find emails, that it can get a little confusing.
  • CRM and Drip campaigns are nice-to-have but aren’t as impressive as tools that specialize in those areas.


Like other email finder API tools, offers multiple pricing tiers including a managed service engagement at $2,999/mo. pricing

6. Findthatlead


Findthatlead is another sales prospecting that’s great for sales teams of all sizes. It uses an email finder API to hunt for decision-makers. They offer a suite of tools that include an email drip builder and a Chrome extension. They also have pretty creative methods to find emails. For example, you can search for prospects based on the technology or products that their company uses.


  • Search – A unique email finder API that lets you search for a prospect’s professional email information by name, domain, and technology. The lookup also includes relevant additional information like their connected LinkedIn and company name and other information.
  • Verify – Drop an email address into verify to check the domain, format, and server status to see if it’s mailable.
  • Social – Enter a LinkedIn URL to get professional email information and more. Save money on expensive LinkedIn outreach.


  • Offers plenty of ways to quickly get accurate professional email information.
  • Easy, intuitive, and simple to set up.
  • Includes pretty extensive marketing functionality.


  • Limited ‘free’ features. Unable to use API unless you upgrade.
  • Chrome extension isn’t as extensive as some competitors.

Email Lookup APIs Side-by-Side Comparison

Free Version?PriceEmail FinderEmail VerificationEmail Enrichment?Chrome Extension?
Hunter.ioYesStarts at $49/moYesYesNoYes
Abstract APIYesStarts at $9/moYesYesYesNo
VoilaNorbertYesStarts at $49/moYesYesYesYes
Snov.ioYesStarts at $30/moYesYesYesYes

Understanding Email Verification APIs

Email Verification APIs work by sending an HTTP request along with a few parameters to the verification service. The service may check the email for the correct syntax, such as the “@” symbol, and for a top-level domain. They will typically perform a variety of other checks:

  • Domain Verification: the API queries the domain’s DNS records to verify the domain’s MX (Mail Exchange) records, which indicates if the email servers are responsible for handling incoming mail.
  • SMTP Verification: The API tries to simulate the email delivery process by sending messages to the server. This is known as Simple Mail Transfer Protocol (SMTP). Based on the server’s response, the API can determine if the email address is deliverable or undeliverable.
  • Role Account and Disposable Email Verification: A good verification API can identify role-based email addresses (like info@ or accounting@) and can check for disposable or fake email addresses.

Different services offer different methods. In most cases, you’ll also need the services API key.

Features to Consider When Choosing an Email Verification API

If you’re considering an Email Verification API you should choose one that includes enough information to help you easily filter not just invalid emails, but disposable or fake email addresses. This way, you can avoid sending marketing emails to unqualified prospects. Make sure you understand the methods that the API is using to verify emails, and that they are thorough enough.

You’ll also want to ensure that the default API response time is acceptable, especially as you begin scaling your efforts. Also, make sure your API comes with plenty of documentation so that you can understand how to implement it and test it for yourself.

Benefits of Email Verification APIs

With the right Email Verification system and API, you can scale your email verification efforts much faster than you ever would without one. With an Email Verification API, you can save your brand’s sending reputation, improve deliverability, and keep your sales and marketing teams on track.

Top Email Verification APIs on the Market

Exploring Email Validation APIs

While Email Verification and Email Validation sound similar, they’re different. Verification has to do with if the email is valid if it’s reliable, and if it’s deliverable. Validation, on the other hand, checks the syntax of the email address for proper formatting. Validation works by using regular expression (regex) to check for proper syntax.

Email validation can also check whether or not the email address is valid and exists in the domain.

Features to Consider When Choosing an Email Validation API

When choosing an email validation tool, you should evaluate the logic it uses to evaluate syntax. Can it suggest corrections and errors too? You also need to ensure it can be used in bulk, and not just on one-off email checks.

Benefits of Email Validation APIs

With an Email Validation tool, you save the time and effort of cleaning up invalid or inaccurate email addresses. You also ensure your sender’s reputation is saved and limit the number of outgoing bounces.

Top Email Validation APIs on the Market

  1. ZeroBounce: ZeroBounce is an email validation and scoring service that offers an API for developers.
  2. Kickbox: Kickbox provides an API for email Validation and scoring.
  3. Emailable: Formerly, ‘TheChecker’, Emailable provides an email validation platform that verifies and validates email addresses. It checks for syntax errors, disposable or temporary email addresses, and deliverability issues.
  4. Abstract API: Abstract provides plenty of easy-to-use API libraries to validate, score, and enrich emails.

Diving into Email Enrichment APIs

Email Enrichment APIs work by leveraging different data sources to request additional information about a given email address. The response can include social media profiles, professional networks, domain information, publicly available data, and more.

Features to Consider When Choosing an Email Enrichment API

It’s important to what information your Email Enrichment API can find. For example, some Enrichment APIs don’t return social media information when this may be important for some. Like any API, you want to be sure it’s scalable and can quickly return large amounts of data in single calls.

In general, it’s a good idea to know as much about the enrichment sources as possible, including their reliability.

Understanding Email Scoring APIs

Email Scoring is used to evaluate the quality and reputation of an email sender. It can analyze things like its domain reputation, analyze content for misspells, excessive use of sales or promotional language, and other forms of spam.

It can also analyze previous email engagement and check if it passes authentication and compliance protocols like SPF, DKIM, and DMARC.

Features to Consider When Choosing an Email Scoring API

If you’re looking for an Email Scoring API, you should understand the mechanisms it uses to verify scoring. It should be able to analyze text and consult blocklist databases.

By using an Email Scoring API, you can detect fraudulent or risky email messages as well as continuously monitor your own email score to make sure your prospects are receiving your emails.

Top Email Scoring APIs on the Market

  1. SendGrid: SendGrid offers an Email Validation API that provides real-time email address validation and scoring.
  2. ZeroBounce: ZeroBounce is an email validation and scoring service that offers an API for developers.
  3. Kickbox: Kickbox provides an API for email verification and scoring.
  4. NeverBounce: NeverBounce offers an API for real-time email verification and scoring and verifies email addresses, detects invalid or risky addresses, and provides a quality score.
  5. MailboxValidator: MailboxValidator provides an API for email validation and scoring. It verifies email addresses, detects disposable or temporary email addresses, and provides a quality score for each address.
  6. Abstract API: Abstract provides plenty of easy-to-use API libraries to validate, score, and enrich emails.

Examining Email Finding APIs

An email finder API is a tool that allows developers to programmatically search for and retrieve email addresses associated with specific individuals, companies, or domains.

To use an email finder API, you typically provide relevant input data for the HTTP request. This can include parameters such as the person’s name, company name, domain, or any other relevant details that can help narrow down the search. You may also need an API and secret key.

The API interacts with large databases or uses web crawling techniques to search for publicly available information, which can involve scraping websites, social media profiles, online directories, and other sources where email addresses might be listed. It then returns an XML or JSON response that includes the email or list of emails requested.

Features to Consider When Choosing an Email Finding API

If you’re looking for an email-finding API, you’ll want to make sure to compare it with similar tools.

Filtering and Search Response Capabilities – A robust email-finding API should offer flexible search and filtering options. Look for features such as searching by name, domain, company, or other relevant parameters to refine your queries and obtain more targeted results.

Email Verification and Validation: Some email-finding APIs provide built-in email verification and validation capabilities. These features can validate that an email address is valid, properly formatted, and deliverable.

Criteria for Selecting the Best Email Lookup API

  • Accuracy. Accuracy is the most important criterion – if it’s not accurately finding the right email, it’s not worth much!
  • Speed. It’s important to consider speed when looking for an Email Lookup tool or API – especially if you plan on making multiple requests.
  • Data Quality. Data from your Email Lookup API should remain reliable.
  • Integration. Can the Email Lookup API integrate easily with other services like a CRM, marketing automation platform, or iPAAS?
  • Support and Documentation. Check for a thriving community of developers or plenty of accessible API documentation.
  • Pricing. It has to be within your budget. Many Email Lookup API providers offer flexible pricing options and free or freemium plans.


Email remains one of the most effective ways to reach prospects and having the right email is critical to success. Evaluating email lookup tools goes far beyond simply finding the email and many times includes validation, verifying, enriching, and scoring.

It’s important to evaluate your needs before selecting a tool and with any email outreach, stay compliant!


What is an Email Lookup API?

An Email Lookup API is an API that allows you to send parameters through an HTTP request or to retrieve additional information about an email to help verify, validate, or enrich it. Email lookup APIs are commonly used in multiple applications like CRMs, marketing platforms, fraud detection systems, and user management systems, to enhance data quality, and improve email deliverability.

What is the difference between email verification and email validation?

Email Validation is about checking for syntax and formatting issues but does not make assumptions about an email’s deliverability or reputation. Email Verification, on the other hand, checks that an email is actively maintained and capable of receiving messages. It helps identify and remove invalid or inactive email addresses from your mailing lists, reducing bounce rates and improving the effectiveness of email campaigns.

How do I choose the best email lookup API for my needs?

Choosing the right email lookup API is like choosing any other product. It’s about comparing features and benefits. Remember to check reviews on accuracy and quality, as well as performance metrics. It’s also important to review the pricing structure carefully – although costs for each call can be a fraction of a cent, they can add up fast.

What are some common use cases for email lookup APIs?

Use cases for email lookup APIs include sales prospecting, marketing, and research, customer support, contact enrichment, and database management.

What are the benefits of using email lookup APIs?

The benefits of using an email lookup APIs are numerous. You can save time spent on prospecting, quickly gather information about the right decision maker, enrich your prospect database, easily reach out to customers, and verify emails before sending to save your sender reputation.

How much does an email lookup API cost?

An email lookup API service ranges in price. Most providers offer some sort of freemium plan with the ability to purchase additional credits or pay a monthly subscription.

How do I avoid abuse and spam complaints when using an email lookup API?

To avoid spam complaints, you should always seek consent, provide ways to opt-out, and continuously monitor and respond to complaints. You should also consider using a reputable email service provider.

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