Regular expression validation for email address

Regular expression validation for email address


Online marketers rely heavily on email marketing campaigns to boost revenue for their businesses. A marketing campaign is considered a success if most of the emails are delivered and read by their audience. Therefore, marketers need to validate email list every once in a while because email addresses become inactive all the time. There are some marketers that only use regular expression validation to check the syntax of the email address before sending out emails. Amidst the hustle, inexperienced marketers tend to make some common mistakes like this.

Is regular expression validation sufficient?

There are many reasons why using regular expression validation alone is insufficient to ensure deliverability of emails. RFC specifications are the industry standards that state how the email address syntax is formed. However, these technical criteria can get pretty complicated to validate. Most people will find it tough to cover all possible syntaxes of an email address using regular expressions.

An important point to note is that even an RFC-compliant email address may not exist. The domain or the mailbox itself could be non-existent. No way to tell just by using regular expression validation.

In addition, regular expression validation cannot determine if an email address is from a disposable provider. Fraudsters hide behind a disposable or temporary email address to make purchases with stolen credit card info.

Marketers should use a proper email validation service

As mentioned above, regular expression validation is severely limited. On the other hand, MailboxValidator can perform checks from multiple angles for a more thorough validation. Firstly, it checks the email address syntax via regular expression validation. Next, the domain existence is verified along with the MX record. This can tell us that the email domain is most likely active and receiving emails.

Then, MailboxValidator will check if the mail server (MX server) is responsive by making a connection to it. Once that is confirmed, it tests if the email address exists. During the validation process, the email domain will be flagged if it comes from a free or disposable email provider.

Benefits of using an email validation service

It is obvious that using an email validation service gives more benefits versus just using regular expression validation. You can find active emails and reachable ones after validating your email list as a result. Then, when marketers send out emails to their mailing list, the open and click rates will be high. As an additional bonus, they will see bounce rate plummet to a minimum during an email campaign.

The ability to check if an email is from a free or disposable email provider is equally important too. Manually review any order made with a free email address to minimize frauds. Anyone using a disposable email address is up to no good. Do not allow them to make any purchase or sign up for services. Definitely don’t send any emails to those addresses.


Regular expression validation is woefully inadequate in a today’s high fraud environment. Marketers or anyone sending out emails campaigns must validate their email list regularly with MailboxValidator to avoid a high bounce rate.

MailboxValidator has a free API plan that gives 300 validations every 30 days. Use that and reduce bounce rate to save money and reputation. Only allow genuine customers to make purchases.

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