Email Address Format Validator

As a software developer or tester of Web applications, you are required to know what is a valid email address and what is an invalid email address. According the Internet specifications, there are a number of valid email address formats. This page allows you to learn and test email address of all formats.

What is a valid email address?

According to the Internet specification RFC 2822, there are several formats of valid email addresses, like john@host.net, john@[10.0.3.19], "John Gate"@host.net or "John Gate"@[10.0.3.19]. Many email address validators on the Web failed to recognize some of those valid email addresses.

Some examples of invalid email addresses are:

  • john@box@host.net - Two at signs (@) are not allowed.
  • .john@host.net - Leading dot (.) is not allowed.
  • john@-host.net - Leading dash (-) is not allowed in on domain name.
  • john@host.web - (web) is not a valid top level domain.
  • john@[10.0.3.1999] - Invalid IP address.

How to test email address format?

In order to help your programming or testing tasks, FYIcenter.com has designed this online testing page for you to validate any given email address using PHP regular expressions.

All you need to do is to enter an email address in the form below and click the Start button.

Email Address:

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