You can test the online email validation service here. Enter up to 10 comma seperated Email addresses in the text box. Select the Validation Level. Each Validation Level is inclusive of the ones before it and all validation results will be returned for each level that is checked. For instance checking SMTP level will also check the domain and the syntax and will return True/False validation results for those checks but will not check and therefore will not return a value for the Mailbox validation. The overall performance of this script depends on the level of checking you choose and the response times of the email domains validated. In Production you would have to decide how much time you wanted to spend on this operation and choose your validation level based on that.

• Syntax - Check email syntax only.
• Domain - Checks that the email address domain exists and is reachable.
• SMTP - Checks that the email address domain has an SMTP service running on it.
• Mailbox - Checks that the SMTP server on this domain has a mailbox for this address.