Best Email APIs in 2026

The top 15 of 37 free Email APIs, ranked by how easy they are to start with (API key, HTTPS, CORS), how reliable they are in our daily health checks, and what developers rate them. Kickbox API takes the top spot.

Last tested Oct 24, 2026 · Rankings update daily

1
Kickbox API
Online · 1026 ms
Email verification API. A free email API by Powered by Kickbox.
- No API key needed
- Callable from the browser (CORS)
- HTTPS
No authHTTPSCORS
2
mail.gw API
Online · 546 ms
API for creating temporary email accounts.
- No API key needed
- Callable from the browser (CORS)
- HTTPS
No authHTTPSCORS
3
mail.tm API
Online · 454 ms
Temporary Email Service. A free email API by Mail.tm.
- No API key needed
- Callable from the browser (CORS)
- HTTPS
No authHTTPSCORS
4
MailSenpai DNS Check API
Online · 805 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
- Callable from the browser (CORS)
- HTTPS
No authHTTPSCORS
5E
Email Validator by LifeStep API
Online · 1178 ms
Validate email syntax and MX, detect disposable/role addresses, suggest typo fixes.
- No API key needed
- Callable from the browser (CORS)
- HTTPS
No authHTTPSCORS
6
Disify API
Online · 1344 ms
Validate and detect disposable and temporary email addresses.
- No API key needed
- Callable from the browser (CORS)
- HTTPS
No authHTTPSCORS
7
DropMail API
Online · 565 ms
GraphQL API for creating and managing ephemeral e-mail inboxes.
- No API key needed
- HTTPS
No authHTTPSCORS ?
8
Guerrilla Mail API
Online · 533 ms
Disposable temporary Email addresses. A free email API by Guerrilla Mail API.
- No API key needed
- HTTPS
No authHTTPSCORS ?
9
Best Temp Mail API
Online · 598 ms
Disposable inboxes for automated email testing, with OTP extraction.
- No API key needed
- HTTPS
No authHTTPSNo CORS
10
Cloudmersive Validate API
Online · 622 ms
Validate email addresses, phone numbers, VAT numbers and domain names.
- Callable from the browser (CORS)
- HTTPS
apiKeyHTTPSCORS
11
EmailJS API
Online · 505 ms
Send emails directly from client-side JavaScript without a backend server.
- Callable from the browser (CORS)
- HTTPS
apiKeyHTTPSCORS
12
Mailfornet API
Online · 788 ms
Disposable inboxes for end-to-end signup tests, with long-polling and HMAC-signed webhooks.
- Callable from the browser (CORS)
- HTTPS
apiKeyHTTPSCORS
13
SMTPfast API
Online · 783 ms
Send transactional email, manage contacts and broadcasts, free 3,000 emails/month.
- Callable from the browser (CORS)
- HTTPS
apiKeyHTTPSCORS
14
Atomic Mail API
Online · 357 ms
Email for AI agents: programmatic inbox creation and send/receive over JMAP.
- Fast: 357 ms response
- HTTPS
apiKeyHTTPSCORS ?
15
MailCheck.ai API
Online · 2357 ms
Prevent users to sign up with temporary email addresses.
- No API key needed
- HTTPS
No authHTTPSCORS ?

Email APIs compared

Top Email APIs compared
API	API key	HTTPS	CORS	Uptime	Response	Rating
Kickbox	No	Yes	Yes	Up	1026 ms	Not rated
mail.gw	No	Yes	Yes	Up	546 ms	Not rated
mail.tm	No	Yes	Yes	Up	454 ms	Not rated
MailSenpai DNS Check	No	Yes	Yes	Up	805 ms	Not rated
Email Validator by LifeStep	No	Yes	Yes	Up	1178 ms	Not rated
Disify	No	Yes	Yes	Up	1344 ms	Not rated
DropMail	No	Yes	Unknown	Up	565 ms	Not rated
Guerrilla Mail	No	Yes	Unknown	Up	533 ms	Not rated
Best Temp Mail	No	Yes	No	Up	598 ms	Not rated
Cloudmersive Validate	Required	Yes	Yes	Up	622 ms	Not rated

More Email APIs

Best Email API FAQ

What is the best free Email API in 2026?

Based on access, reliability and developer ratings, the top free Email APIs right now are Kickbox API, mail.gw API and mail.tm API. Kickbox API ranks first. Rankings update daily from health checks of all 37 Email APIs in the directory.

What is the best Email API without an API key?

Kickbox API, mail.gw API and mail.tm API need no API key, so you can call them without signing up. 13 of the 37 ranked Email APIs are keyless.

Which Email API works from the browser?

Kickbox API, mail.gw API and mail.tm API support CORS over HTTPS, so front-end JavaScript can call them directly without a proxy.

How are these APIs ranked?

Each API gets a score from: no API key (+), HTTPS (+), CORS support (+), 30-day uptime and response time from our daily health checks, and ratings from developers on this site. APIs that failed three checks in a row are left out until they recover.