Email Verification APIs
Email verification APIs check syntax and MX records and, in many cases, whether the mailbox accepts mail over SMTP. Disify flags disposable addresses without a key, Abstract Email Validation and mailboxlayer run full deliverability checks on freemium plans, and UserCheck suggests typo corrections. For list cleaning, uChecker and MailValid handle bulk verification.
| API | Pricing | Auth | Format | Free tier | Status |
|---|---|---|---|---|---|
Abstract Email Validation APIChecks whether an email address is real and deliverable via syntax, MX, and SMTP checks. Identity & Security › Email Verification | Freemium | API key | JSON | <100/day | Live |
ApexVerifyPay-as-you-go API that verifies email addresses and phone numbers in real time. Identity & Security › Email Verification | Free trial | API key | JSON | — | Untested |
Cloudmersive ValidateValidates email deliverability, phone numbers, EU VAT IDs, addresses and domains in one family. Identity & Security › Email Verification | Freemium | API key | JSON | <100/day | Live |
DisifyChecks email syntax, DNS/MX records, and flags disposable or temporary email addresses. Identity & Security › Email Verification | Freemium | None | JSON | — | Live |
EmailvalidationChecks an email's syntax, MX records, deliverability and disposable/free-domain status. Identity & Security › Email Verification | Freemium | API key | JSON | <100/day | Live |
HeybounceReal-time email verification checking deliverability, MX records, and disposable/role addresses. Identity & Security › Email Verification | Free trial | API key | JSON | — | Live |
Kickbox Disposable Email CheckerChecks whether an email domain belongs to a disposable/temporary-address provider. Identity & Security › Email Verification | None | JSON | Unlimited | Live | |
mailboxlayerValidates email syntax, SMTP deliverability, disposable/role addresses and catch-all domains. Identity & Security › Email Verification | Freemium | API key | JSON | <100/day | Live |
MailboxValidatorChecks if an email address is deliverable, disposable, or from a free provider like Gmail. Identity & Security › Email Verification | Freemium | API key | JSON | <100/day | Live |
MailValidReal-time and bulk email verification: deliverability, catch-all, disposable, and role checks. Identity & Security › Email Verification | Freemium | API key | JSON | — | Live |
NoParamChecks email addresses in real time for valid syntax, MX records, and disposable or role addresses. Identity & Security › Email Verification | Freemium | API key | JSON | <100/day | Untested |
ProWebLook Email VerificationChecks email syntax, MX records, SMTP mailbox status and disposable-address detection Identity & Security › Email Verification | Paid | API key | JSON | — | Live |
RankFabrik VerifySMTP-level email verification (valid/invalid/risky/unknown) that stops before sending, billed per result. Identity & Security › Email Verification | Freemium | API key | JSON | <100/day | Live |
uCheckerValidates whether an email address exists via SMTP/DNS checks, singly or in bulk up to millions of addresses. Identity & Security › Email Verification | Freemium | API key | JSON | — | Live |
UserCheck (formerly MailCheck.ai)Flags disposable, role, and forwarding email addresses and suggests typo corrections via MX/domain checks. Identity & Security › Email Verification | Freemium | API key | JSON | <100/day | Live |
Abstract Email Validation APIFreemiumLive
Checks whether an email address is real and deliverable via syntax, MX, and SMTP checks.
API key · JSON
<100/day
OpenAPI spec · llms.txt
ApexVerifyFree trialUntested
Pay-as-you-go API that verifies email addresses and phone numbers in real time.
API key · JSON
—
no machine-readable spec
Cloudmersive ValidateFreemiumLive
Validates email deliverability, phone numbers, EU VAT IDs, addresses and domains in one family.
API key · JSON
<100/day
OpenAPI spec
DisifyFreemiumLive
Checks email syntax, DNS/MX records, and flags disposable or temporary email addresses.
None · JSON
—
no machine-readable spec
EmailvalidationFreemiumLive
Checks an email's syntax, MX records, deliverability and disposable/free-domain status.
API key · JSON
<100/day
llms.txt
HeybounceFree trialLive
Real-time email verification checking deliverability, MX records, and disposable/role addresses.
API key · JSON
—
no machine-readable spec
Kickbox Disposable Email CheckerLive
Checks whether an email domain belongs to a disposable/temporary-address provider.
None · JSON
Unlimited
no machine-readable spec
mailboxlayerFreemiumLive
Validates email syntax, SMTP deliverability, disposable/role addresses and catch-all domains.
API key · JSON
<100/day
llms.txt
MailboxValidatorFreemiumLive
Checks if an email address is deliverable, disposable, or from a free provider like Gmail.
API key · JSON
<100/day
OpenAPI spec · llms.txt
MailValidFreemiumLive
Real-time and bulk email verification: deliverability, catch-all, disposable, and role checks.
API key · JSON
—
OpenAPI spec · llms.txt
NoParamFreemiumUntested
Checks email addresses in real time for valid syntax, MX records, and disposable or role addresses.
API key · JSON
<100/day
llms.txt
ProWebLook Email VerificationPaidLive
Checks email syntax, MX records, SMTP mailbox status and disposable-address detection
API key · JSON
—
OpenAPI spec · llms.txt
RankFabrik VerifyFreemiumLive
SMTP-level email verification (valid/invalid/risky/unknown) that stops before sending, billed per result.
API key · JSON
<100/day
llms.txt
uCheckerFreemiumLive
Validates whether an email address exists via SMTP/DNS checks, singly or in bulk up to millions of addresses.
API key · JSON
—
OpenAPI spec
UserCheck (formerly MailCheck.ai)FreemiumLive
Flags disposable, role, and forwarding email addresses and suggests typo corrections via MX/domain checks.
API key · JSON
<100/day
llms.txt
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Choosing an Email Verification API
Is there a free Email Verification API?
Yes. Abstract Email Validation API, mailboxlayer, Disify, Cloudmersive Validate, Emailvalidation and 6 others have a free tier alongside paid plans.
Which Email Verification APIs work without an API key?
Disify and Kickbox Disposable Email Checker need no key or sign-up, so you can try them with a plain request.
Can I call an Email Verification API from front-end JavaScript?
Disify and Kickbox Disposable Email Checker allow cross-origin requests and need no key, so they work straight from the browser. For the others, call them from your server so your key stays private.
Can I use Email Verification APIs in a commercial project?
Abstract Email Validation API, ApexVerify, Cloudmersive Validate, Heybounce, MailValid and 2 others permit commercial use. mailboxlayer restricts it, for example to non-commercial or attributed use, so read the terms first.
Which Email Verification APIs work with AI agents?
Abstract Email Validation API, Cloudmersive Validate, MailboxValidator, MailValid, ProWebLook Email Verification and 1 other publish an OpenAPI spec for generating clients and tools.
More in Identity & Security: Auth APIs · Phone Validation APIs · Fraud Detection APIs · Threat Intel APIs · Background Checks APIs · KYC & Identity Verification APIs · Website Security APIs
Related: Email APIs · Disposable Email APIs