Why you need to verifiy an email address and not just validate its format
A user who registers on your website and types a typo on his address will not understand why he does not receive a confirmation email and will abandon his registration thinking that your site is faulty.
Even worse, if you periodically send messages to mailing lists that contain email addresses that do not exist, they will bounce back, and your domain name will end up being considered a spam domain and receive penalties, which will ruin the deliverability of all your emails.
Therefore, verifying an email address is essential to improve the success rates of all things related to your users' email addresses and improve your business.
How to validate and verify an email address
The validation of an email address must be limited to a minimum set of rules. According to the RCF 2822, the email box's name (before the @) can contain any characters, including spaces. On the other hand, concerning the domain name (after the @), it is enough to ensure a dot's presence.
In terms of verification, however, a much more complex system is required. The verification script must verify that the domain name exists. It must also query the DNS records and check that it contains MX fields, which indicate the domain's email servers' addresses. And from these addresses, check that the SMTP servers exist and are working. Implementing such a system by yourself could be a waste of your time, especially knowing there is an efficient and free web service that does all this.
Validate and verify an email address with an API
Abstract provides a free email address validation API service.
The service is fast and can be queried using a simple GET request. Abstract checks the email address format, the domain configuration, and the presence of an SMTP server. It will also detect if the email address is provided by a disposable email service, which is a good thing to know before accepting a user account creation.
The documentation is clear and precise, and you will be ready to use the API in seconds.
