Unitpost API alternatives

Send transactional email, campaigns and SMS; free for 5,000 emails a month. If it doesn't fit your project, here are the 10 best free Email APIs to use instead in 2026, out of 46 in the directory.

For reference, Unitpost API: HTTPS.

1. 1

   Cloudmersive Validate API

   Online · 174 ms

   Validate email addresses, phone numbers, VAT numbers and domain names.

   • 100% uptime (30 days)
   • Fast: 174 ms response
   • Callable from the browser (CORS)
   • HTTPS

   apiKeyHTTPSCORS
2. 2

   Kickbox API

   Online · 754 ms

   Email verification API. A free email API by Powered by Kickbox.

   • No API key needed
   • 100% uptime (30 days)
   • Callable from the browser (CORS)
   • HTTPS

   No authHTTPSCORS
3. 3

   mail.gw API

   Online · 602 ms

   API for creating temporary email accounts.

   • No API key needed
   • 100% uptime (30 days)
   • Callable from the browser (CORS)
   • HTTPS

   No authHTTPSCORS
4. 4

   mail.tm API

   Online · 625 ms

   Temporary Email Service. A free email API by Mail.tm.

   • No API key needed
   • 100% uptime (30 days)
   • Callable from the browser (CORS)
   • HTTPS

   No authHTTPSCORS
5. 5

   StopMailing API

   Online · 738 ms

   Disposable email addresses with a free, no-signup REST API.

   • No API key needed
   • 100% uptime (30 days)
   • Callable from the browser (CORS)
   • HTTPS

   No authHTTPSCORS
6. 6

   Vetto API

   Online · 1170 ms

   Check email domains in bulk for disposable providers and dead domains, no key needed.

   • No API key needed
   • 100% uptime (30 days)
   • Callable from the browser (CORS)
   • HTTPS

   No authHTTPSCORS
7. 7

   Email Validation API

   Online · 742 ms

   Validate email addresses for deliverability and spam.

   • 100% uptime (30 days)
   • Callable from the browser (CORS)
   • HTTPS

   apiKeyHTTPSCORS
8. 8E

   Email Validator by LifeStep API

   Online · 1006 ms

   Validate email syntax and MX, detect disposable/role addresses, suggest typo fixes.

   • No API key needed
   • 100% uptime (30 days)
   • Callable from the browser (CORS)
   • HTTPS

   No authHTTPSCORS
9. 9

   EmailJS API

   Online · 685 ms

   Send emails directly from client-side JavaScript without a backend server.

   • 100% uptime (30 days)
   • Callable from the browser (CORS)
   • HTTPS

   apiKeyHTTPSCORS
10. 10

    MailSenpai DNS Check API

    Online · 1464 ms

    Check a domain's SPF, DKIM, DMARC and MX records and get what to fix, with the values to publish.

    • No API key needed
    • 100% uptime (30 days)
    • Callable from the browser (CORS)
    • HTTPS

    No authHTTPSCORS

Unitpost API vs alternatives

Unitpost API compared with its alternatives

API	API key	HTTPS	CORS	Uptime	Response	Rating
Unitpost	Required	Yes	No	Up	2737 ms	Not rated
Cloudmersive Validate	Required	Yes	Yes	100%	174 ms	Not rated
Kickbox	No	Yes	Yes	100%	754 ms	Not rated
mail.gw	No	Yes	Yes	100%	602 ms	Not rated
mail.tm	No	Yes	Yes	100%	625 ms	Not rated
StopMailing	No	Yes	Yes	100%	738 ms	Not rated
Vetto	No	Yes	Yes	100%	1170 ms	Not rated
Email Validation	Required	Yes	Yes	100%	742 ms	Not rated
EEmail Validator by LifeStep	No	Yes	Yes	100%	1006 ms	Not rated

See also: best Email APIs · all Email APIs