Verify if an email address exists at Verify-Email.org, VerifyEmailAddress.io or Email-Validator.net by inputting the email address to be verified in the provided text box and pressing Enter; the site's program does the checking automatically. These sites check the validity of the syntax or format of the email address and the existence of a mail server for the domain. Finally, the email checker simulates sending a message to the email address mailbox.
Verify-Email.org, VerifyEmailAddress.io and Email-Validator.net all provide a service to validate email addresses, although Verify-Email.org only allows five free searches per hour and VerifyEmailAddress.io only allows up to 20 free email searches a day. For users who have a lot of addresses to check, these sites also offer premium services for application program interface or bulk email verification. Bulk email verification works by submitting the email list to be checked to the service provider. An alternative is to embed an API on the client website that automatically verifies emails as they are submitted to the site during user registration.
Verify-Email.org offers tiered monthly and annual subscriptions plans for both bulk email verification or use of the API for up to 500,000 emails a month. These plans also include a specific number of free email checks on the website. VerifyEmailAddress.io and Email-Validator.net offer similar premium services, but Email-Validator.net also offers free checking of postal addresses and phone numbers.
As an alternative, verify email addresses manually by pinging the email address. This requires familiarity with using the computer's MS-DOS prompt or Windows command line, and might only be a feasible option for more technically inclined users.