
Validate email address to improve deliverability.
MailboxValidator API is a free Email API that requires apiKey authentication, is served over HTTPS and has unconfirmed CORS support.
MailboxValidator provides free email API that checks if an email address is from a free email provider.
Details from mailboxvalidator.com.

Unified API suite · now live
Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
Disposable inboxes for end-to-end signup tests, with long-polling and HMAC-signed webhooks
Free email validation: MX check, disposable detection, syntax
Verify email deliverability with a strict yes/no, disposable and catch-all detection
The MailboxValidator API is provided by MailboxValidator (mailboxvalidator.com). MailboxValidator provides free email API that checks if an email address is from a free email provider.
Yes. The MailboxValidator API is listed in the Email category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
Yes. The MailboxValidator API uses apiKey authentication, so you need to register for credentials before making requests.
CORS support for the MailboxValidator API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The MailboxValidator API is served over HTTPS, so it's safe to use in production.