mailfloss API alternatives

Stop spam signups: block disposable and invalid emails and suggest typo fixes. 500 free 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, mailfloss API: 100% uptime (30 days) · Callable from the browser (CORS) · HTTPS.

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
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
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
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
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
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
Email Validation API
Online · 742 ms
Validate email addresses for deliverability and spam.
- 100% uptime (30 days)
- Callable from the browser (CORS)
- HTTPS
apiKeyHTTPSCORS
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
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
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

mailfloss API vs alternatives

mailfloss API compared with its alternatives
API	API key	HTTPS	CORS	Uptime	Response	Rating
mailfloss	Required	Yes	Yes	100%	2077 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
Email Validator by LifeStep	No	Yes	Yes	100%	1006 ms	Not rated

See also: best Email APIs · all Email APIs

mailfloss API alternatives FAQ

What is the best free alternative to the mailfloss API in 2026?

The top-ranked free alternatives to the mailfloss API are Cloudmersive Validate API, Kickbox API and mail.gw API, all in the Email category. Rankings combine access (API key, HTTPS, CORS), daily uptime checks and developer ratings.

Is there a mailfloss API alternative that doesn't need an API key?

Yes: Kickbox API, mail.gw API and mail.tm API work without an API key, unlike the mailfloss API, which uses apiKey authentication.

How many Email APIs are similar to the mailfloss API?

The directory lists 43 other free Email APIs. This page compares the top ones side by side.