15 Best Email Validation APIs
Most businesses spend a long time cultivating an email list to keep in touch with customers or share promotions. But when it comes to email marketing lists, bigger is not always better.
Sending blasts to huge lists that haven’t been verified can result in hard bounces and undeliverable emails. Every email marketing pro knows it’s important to avoid that, because it can hurt sender reputation and result in your emails ending up in the dreaded spam folder.
But manually verifying email addresses is incredibly difficult. In fact, it’s virtually impossible…unless you have an appetite for combing your email list for long strings of numbers or those that are obviously fake, like those involving obscenities!
Fortunately, as we’ll see below, there’s a much better way to validate email addresses and improve sender reputation. Enter the email validation API…
Why Is Email Validation Important?
As we’ve touched on above, email validation is a critical step in the email marketing process because it helps avoid things like:
- High bounce rates
- Poor deliverability
- Inaccurate open rates
- Being blacklisted by mailbox providers
Although a high number of bouncebacks isn’t necessarily as damaging as spam complaints, both of which can happen when you buy email lists, it’s still a bad thing.
A high bounce rate, particularly hard bounces, can impact your future deliverability because email providers monitor bounce rates. If enough of your emails bounce, you might find that your emails go straight to spam folders or that you end up on email provider blocklists.
What is an Email Validation API?
An email validation API is a tool that automates the process of weeding out typos, fake email addresses and disposable emails from your email list. This helps to ensure that your emails are going to people who signed up for them and stand some chance of opening them.
Disposable email addresses are often used to bypass registration forms or lead pages that collect emails, and expire after a short period of time. Some of them spit out strings of random letters and numbers, while others create email addresses that look surprisingly real…if a little uncanny valley-ish.
Two commonly used providers include 10minutemail.com and minuteinbox.com, which any of the best email validation API products on the market will be able to spot.
Beyond that, email validation tools follow a set of processes, outlined below, that hunt out (and remove) disposable and invalid addresses that might be lurking in your email list to improve email deliverability.
How Do Email Verification APIs Work?
Before it gets into technical stuff, a bulk email verification API starts by doing exactly the sort of thing that a real person might do when searching for email addresses that don’t look right, i.e. looking for addresses that end in gmial.com or contain special characters such as ™ or ∃.
They’ll also remove disposable email addresses (DEAs) like erugiwefiu3248@dgeroe.com and, potentially, role-based email names like info@ or admin@ as these can also affect email deliverability. Finally, they’ll remove spam traps — addresses created by ISPs to identify and block spam email.
But an email validation API goes beyond what humans could do by hand. That includes verifying MX (Mail Exchange) records, pinging requests to email address servers to verify that they’re active, and running emails through a DNSBL (DNS-based blackhole list) and URI (Uniform Resource Identifier) DNSBL to search for spam email addresses and domains.
15 [Top] Email Validation APIs to Preserve Your Reputation
There are plenty of real time verification API offerings on the market in 2021. In fact, there are so many products available that actually choosing a service can be a bit daunting. In the following section, you’ll find 15 different email verifier APIs currently available.
Each one has its own advantages and disadvantages, but our aim here was to provide an unbiased overview of various options rather than review every single bulk email verification service. We have included publicly available ratings, provided by existing users, and key features highlighted by these email validation tools on their main sites.
With that said, it might be worth taking advantage of a few free trials to figure out which one you find most appealing. Ultimately, the best email verification API is one that you can actually see yourself using in your email marketing efforts on a daily or monthly basis.
It’s also worth noting that some of the services listed below are standalone products, while others form one part of a larger toolset. We’ve tried to reflect this in the pricing below where possible, but it goes a way towards explaining some of the discrepancies between services.
Abstract’s Email Validation API
Abstract’s Email Verification API is part of a suite of 16 different APIs used by 10,000+ developers, with a transparent “per request” pricing model. It’s organized around REST principles, and there’s no obligation to use (or pay for) their other APIs too.
Abstract’s users include organizations like Accenture, NOKIA, Google, and Airbnb, which speaks to their APIs being capable of scaling, and they’re known for reliable uptime too. You can add your lists in a couple of different ways, and API responses are returned in JSON.
Other real time verification API products available here include phone validation, IBAN validation, and VAT validation, which might prove useful for individuals or organizations looking for more than just an email verification tool.
Features
- Real-time MX and SMTP check
- Typo checking and smart suggestion
- Disposable and free email providers check
- Privacy friendly (GDPR, CCPA)
- Role checking and filters
Pricing
First 100 requests free, paid plans starting at $9 for 5,000 requests per month
Rating
Sourceforge: 5/5
SendGrid
The SendGrid Email Validation API, while powerful, is just one part of Twilio’s Email Delivery Service. Access is only available to Pro SendGrid users and above, which puts the price point of API usage quite a bit higher than some competitors.
The service is pretty well-regarded in the space, and Twilio has huge cachet as a company, but it might offer a lot more features than you actually need if you’re looking for a standalone email verification API.
Lists can be uploaded as CSV files but, as mentioned above, any and all output is reliant on having an active SendGrid account.
Features
- Machine learning and mailbox provider-friendly tactics
- Identify mistyped, inactive, non-existent, disposable, or shared emails
- Avoid losing contacts due to accidental typos
- Remove additional fields like email address confirmation
- Doesn’t use broken SMTP handshake
- GDPR compliance
Pricing
SendGrid Pro starts at $89.95 per month
Rating
Capterra: 4.2/5
G2: 4/5
Mailgun
Mailgun claims to have the fastest email validation API on the market in 2022. Used by leading brands like Microsoft, Dell, Anheuser Busch and NHL, there’s no doubt that this service (created by sinch) has serious enterprise credentials.
Possible list formats include CSV and JSON.
Features
- Lightning-fast Email Verification
- MX/mailbox verification
- Role-based address verification
- Disposable and duplicate email removal
- Catch-all address verification
- Suggestions for suspected typos
- RFC grammar rule check
Pricing
5,000 emails per month free for 3 months, then $0.80 per 1,000 emails
Rating
G2: 4.4/5
ZeroBounce
ZeroBounce boasts more than 100,000+ clients, including Airbnb and hotjar, claiming 98% accurate email validation. They offer a pay-as-you-go model for their bulk email verification API, as well as monthly subscription options, which offers customers plenty of flexibility.
Lists can be uploaded in a wide range of formats: TXT, CSV, XLSX, or XLS.
Features
- IP address geo-location
- Multiple API keys
- Inbox placement test
- Email server test
- Blacklist monitor
- Detailed status codes
- 18 validation tools
Pricing
100 free monthly email verifications, then $16 for 2,000 emails (pay as you go)
Rating
Capterra: 4.5/5
G2: 4.5/5
DeBounce
DeBounce offers a few different products — bulk email validation, email list monitoring, lead finding, validation on lead capture forms, and data enrichment — in addition to their real time API. You can upload lists in TXT or CSV format, and they offer a free trial.
If you want to get a feel for the performance of their email verifier APIs, you can try out their free disposable detector web tool for identifying valid addresses.
Features
- SMTP checks
- Disposable email checker
- Catch-all domain checker
- Syntax elimination
- Anti-greylisting technology
- Email deduplication
- Removes spam traps
- MTA validation
- Domain confirmation
Pricing
100 free credits, then $10 for 5,000 verifications
Rating
Capterra: 4.6/5
G2: 4.5/5
NeverBounce
NeverBounce places a lot of emphasis on connectivity with 80+ integrations available, including Hubspot, MailChimp, Marketo, Drip, and MailerLite. Their suite of three products — Clean, Verify, and Sync — are all designed to identify incorrect email addresses and keep lists clean.
You can upload lists as a CSV, or hook NeverBounce up with your email service provider.
Features
- Hybrid verification
- Mail server validation
- Free scrubbing
- High-risk detection
- Multiple connection methods
- Tons of integrations with different platforms
- GDPR compliant
- Bank-level security
Pricing
$8 for 1,000 (pay as you go), with free demo credits available
Rating
Capterra: 4.5/5
G2: 4.4/5
Clearout
Used by more than 30,000 businesses, including Adobe and truecaller, Clearout offers email finding and verification services that can be integrated with more than 100 different services. Lists can be uploaded in CSV or XLSX formats, and they also offer phone number verification.
Features
- Anti-greylisting technology
- Catch-all verification
- Syntax check
- Blacklist verification
- Yahoo and AOL validation
- Gibberish check
- Removal of duplicate emails
- Domain verification
- Disposable email verification
- Extended SMTP validation
- Spam trap detection
Pricing
$21 for 3,000 emails (pay as you go)
Rating
Capterra: 5/5
Get Art the API guy’s stories in your inbox
Join Medium for free to get updates from this writer.
G2: 4.8/5
Reacher
Per their own website, Reacher is made by a small independent studio in Paris. That said, their product offers a powerful API and is completely open-source. Built with Rust, using the Warp web framework, Reacher prioritizes speed but claims to be very scalable too.
Features
- MTA validation
- MX record checks
- SMTP checks
- Disposable email checker
- Catch-all domain checker
- Identify role-based accounts
- Checks for hard bounces
- Syntax checks
- Domain confirmation
Pricing
50 emails per month for free, then $69 for up to 10,000 emails per month
Rating
Trustpilot: 3.7/5
Saasworthy: 78%
Hunter
In this space, Hunter is perhaps better known for finding professional email addresses than email verification. With that said, they also offer a powerful Email Verifier API that you can use (in a limited capacity) with a free API key.
It’s worth pointing out that, in their words, “Hunter focuses on B2B. Therefore, webmails are not verified. We’ll run every checker but won’t reach the remote SMTP server.”
Features
- Validate email format
- Gibberish check
- Disposable address check
- Verify webmail email addresses
- Checks for MX records
- SMTP checks
- Checks for accept-all domains
Pricing
50 verifications per month free, then paid plans starting at £36 for 1,000 requests per month
Rating
Capterra: 4.6/5
G2: 4.4/5
Email Hippo
Email Hippo’s “award-winning email verification API” is available in a couple of different editions, with certain features paywalled in the more basic version, as well as an Enterprise plan. That might deter some users, but they do offer a free trial to help potential customers figure out which plan is best for them.
Features
- Finds disposable emails
- Issues a trust score to email addresses
- Finds catch-all mail servers
- Protects against blocklists
- Mail system detection
- Role checks
- MX record checking
- Greylist detection
- Gibberish check
- Mail server location identification
- Dark link web checks
- Spots spam traps
- Freemail detection
- Identifies syntax errors
Pricing
First 100 requests free, paid plans starting at $9.88 for 1,000 requests per month
Rating
Capterra: 5/5
G2: 4/5
Snov.io
Snov.io’s customer list, part of their sleek minimal site, boasts some big names: eBay, Disney, Target, and Walmart, among others. They claim to have verified over 90 million emails in the last year alone, so evidence of their scalability is pretty clear.
In addition to email verification, they offer a range of free extensions for email finding and tracking, technology checking, and mass email merges.
Features
- Email format check
- Gibberish check
- Domain existence check
- Catch-all email and domain search
- Freemail check
- MX record check
- SMTP authentication
Pricing
50 free email verifications per month, then 2,000 per month with a $39 monthly subscription
Rating
Capterra: 4.6/5
G2: 4.5/5
Mailboxlayer
Even a quick look at Mailboxlayer’s main site, with its technical terminology and focus on APIs, reveals that it’s aimed at developers. That idea is backed up by extensive documentation and links to other APIs for weather data, exchange rates, and more.
Features
- Typo and syntax check
- MX record and SMTP verification
- Catch-all detection
- Free and disposable email filtering
- Sender reputation/deliverability score
Pricing
First 100 requests free, paid plans starting at $14.99 for 5000 requests per month
Rating
G2: 4.3/5
WhoisXML
On their main site, WhoisXML calls themselves the “#1 Email Verification Tool” on the market. Whether or not that’s true is up for debate, but they do claim to have verified more than 300 million email addresses…which is impressive. They offer 23 different APIs, including their email verification API, as well as database samples and a disposable email demo tool.
Lists can be uploaded using CSV, or JSON and XML (for download only).
Features
- Identify free email service providers
- Detect disposable/invalid emails
- Verify MX records/IP addresses
- Avoid syntax errors
- Ensure mailbox existence
- Notice catch-all email addresses
Pricing
First 500 queries free, then $30 for 1,000 (pay as you go)
Rating
Gartner: 5/5
Trumail
Trumail is powered by EmailChecker.com. Although it doesn’t have many public reviews, Email Checker received a score of 4.7 from Capterra. So why feature this service here instead of that one? Because it’s an example of an email verification service with a niche.
It’s clear from Trumail’s homepage that they’re targeting developers, right down to the prominent GitHub Star button in the top right corner. Written entirely in Go, Trumail provides output in three different formats: JSON, JSONP and XML.
With bulk email verification and high volume enterprise pricing available on request, this lightweight (but very capable) service is one that might appeal to dedicated developers.
Features
- SMTP verification
- Checks for catch-all domains
Pricing
10 free daily verifications, $14 for 1,000 requests (pay as you go)
Rating
-
Kickbox
On their website, Kickbox is positioned very much as an email verification API (although they do offer a drag and drop service to find valid email addresses too), highlighting their libraries for Node.js, Python, Ruby, PHP, and more. You can test out their API on their website, using working code, for simulated verification results.
Features
- Inbox placement testing
- Blocklist monitoring
- Identify fake or invalid email addresses
- SMTP verification
- Check for disposable/temporary email addresses
- Fix email address typos
- Improve deliverability rates by eliminating bounces
- Support in developer Slack channel
- GDPR compliance
Pricing
First 100 requests free, then $10 for 1,000 verifications (pay as you go)
Rating
Capterra: 4.5/5
G2: 4.1/5
3 Bonus Email Validation Services
If, for some reason, you don’t want to use an API to find valid email addresses then there are some other options available. We’ve listed three browser-based solutions below, and you may notice that two of them are free tasters of more comprehensive services listed above:
Uploading email addresses into services like these is fiddly, and you’ll probably run into daily limits sooner than later. That said, if you only need to check a handful of email addresses at a time (and don’t want to sign up for one of the email validation services with a free plan listed above), one of these email verifier tools might be sufficient.
Conclusion
Trying to handle the email verification process manually is an uphill battle, not least because it’s just not possible for humans to do everything that an email verification API can:
- Identify role-based or suspicious names
- Check syntax against IETF and RFC standards
- Remove spam traps from email lists
- Identify and remove disposable/invalid emails
- Check mailbox activity
- Search for IP addresses using MX records
- Conduct DNSBL and URI DNSBL checks
Even if you could do all of this manually, there’s just no reason to do so when email verification APIs can do it quickly, efficiently, and cheaply. And that gives you more time to focus on your email marketing efforts.
Whether you’re looking to maintain a clean email list, ensure your analytics are accurate, or try to help your emails escape spam folders, an email verification API is worth investing in. And, as we’ve seen above, there are products available to suit every aim and budget.
