Email Domain Validation Regex

Here is the regular expression.

Email domain validation regex. Feeling hardcore or crazy you decide. General email regex rfc 5322 official standard. Older editions of this regex tutorial mentioned b a z 0 9 a z 0 9.

If these three domains do not pass your regular expression may be not allowing legitimate domains. The formal definitions of an email address are in rfc 5322 and rfc 3696 however this article will not follow the above rfc for email validation. However we ll not allow any two consecutive dots or those dots appearing as the initial or final characters in the local part and domain part of the email address.

Also the isvalidemail method doesn t verify that the top level domain name is a valid domain name listed at. If you want to avoid sending too many undeliverable emails while still not blocking any real email addresses the regex in top level domain has two to six letters is a good choice. Net java javascript pcre perl python ruby check whether each part of the domain is not longer than 63 characters and allow internationalized domain names using the punycode notation.

The isvalidemail method merely determines whether the email format is valid for an email address it doesn t validate that the email exists. When choosing a domain validation regex you should see if the domain matches the following. Case insensitive regex flavors.

The isvalidemail method then calls the regex ismatch string string method to verify that the address conforms to a regular expression pattern. Though it obviously allows many things that aren t email addresses such as the regex is quick and simple and will never block a valid email address. Let s continue improving our previous regular expressions to allow both the local part and the domain name part to have at least one dot.

. Read the official rfc 5322 or you can check out this email validation summary note there is no perfect email regex hence the 99 99.