Comparison

Best email validation APIs in 2026

What the common email verification APIs check and what they cost per email.

Updated October 1, 2026 · 2 min read

We make emailvalidation.io, so we are not neutral. Prices are taken from each provider’s pricing page or public pricing summaries in October 2026; check them before you buy.

Overview

APIFreeEntry pricePrice per email
emailvalidation.io100 / month$9.99 / month for 5,000$0.002 (5,000) → under $0.001 (100,000 / month for $94.99)
ZeroBounce100 / month$39 for 2,000 creditsabout $0.02 at the smallest pack
NeverBounce–$0.008 per email up to 10,000$0.005 from 10,000, $0.004 from 100,000
Kickbox100 once$5 for 500$0.008 (5,000) → $0.005 (100,000)

What they check

All four check syntax, DNS/MX and the mailbox over SMTP, and flag disposable and role addresses and catch-all domains. Differences are in extras: ZeroBounce adds activity data and an AI score, Kickbox charges only for deliverable and undeliverable results, and emailvalidation.io returns a quality score and a typo suggestion with every request and also validates uploaded lists in its dashboard.

How to choose

  • Steady monthly volume (sign-up forms, CRM sync): a subscription is cheapest. emailvalidation.io’s plans cost a fraction of pay-as-you-go credits.
  • One big list once a year: pay-as-you-go credits (NeverBounce, Kickbox) avoid a subscription; mind the 12-month credit expiry.
  • Extra data about contacts: ZeroBounce’s activity data.

Try the result quality first: validate a sample of your own addresses with the free email validator.

Frequently asked questions

What is the cheapest email validation API?

For regular monthly volume, subscription plans are cheapest: emailvalidation.io costs $9.99 for 5,000 validations a month (about $0.002 per email). Pay-as-you-go credits at ZeroBounce, NeverBounce and Kickbox cost roughly $0.005–$0.02 per email depending on volume.

Is there a free email validation API?

emailvalidation.io and ZeroBounce both include 100 free validations per month. Kickbox gives 100 free verifications once at sign-up.

Email validation API

Validate emails in your app

emailvalidation.io checks syntax, MX records and the mailbox over SMTP, flags disposable, role and free addresses and returns a quality score, in one request.

Read the docs

100 free validations every month. No credit card required.

GET https://api.emailvalidation.io/v1/info?email=support@emailvalidation.io

{
  "email": "support@emailvalidation.io",
  "domain": "emailvalidation.io",
  "format_valid": true,
  "mx_found": true,
  "smtp_check": true,
  "disposable": false,
  "role": true,
  "free": false,
  "score": 0.64,
  "state": "deliverable",
  "reason": "valid_mailbox"
}

Keep reading

Catch-all email addresses explainedWhat a catch-all (accept-all) domain is, why email verifiers mark these addresses as risky, how to detect catch-all domains and whether you should send to them. Gmail and Yahoo sender requirementsWhat Gmail and Yahoo require from email senders: SPF or DKIM for everyone; SPF, DKIM, DMARC, one-click unsubscribe and a spam rate below 0.3% for bulk senders. Checklist with fixes. How to check if an email address existsHow email verification works: syntax, DNS and MX lookup, and the SMTP RCPT TO handshake that asks the mail server about a mailbox without sending a message. Plus its limits: catch-all, greylisting. How to reduce your email bounce rateWhat hard and soft bounces are, what bounce rate is acceptable, and seven ways to lower it: validation at sign-up, list cleaning, double opt-in, SPF, DKIM and DMARC. Validate email addresses in JavaScriptValidate emails in JavaScript: HTML5 input validation, a practical regex, typo hints, and checking that the mailbox exists with an API call from Node.js. Copy-paste code. Validate email addresses in PHPValidate emails in PHP with filter_var, check MX records with checkdnsrr, and verify the mailbox with an API call using cURL or Guzzle. Laravel validation rule included.

Start using our email validation software today!

Get 100 validations per month for free