An email address consist of three items:
1) email ID,
2) the @ symbol,
3) a domain.
Do you think that email addresses are case sensitive? Maybe you use upper and lower case characters – as in this email address:Lady.Gaga@WildMusic.com
But are emails case sensitive?
The short answer: NO.
The long answer:
Email DOMAINS are explicitly and always case insensitive. The address Lady.Gaga@website.com is exactly equivalent to Lady.Gaga@WEBSITE.com.
Email IDs are allowed to be case sensitive. However, in practice email IDs are usually case insensitive also.
It is rare that an Internet Service Provider (ISP) distinguishes between upper- and lower-case letters in the email ID.
As a standard rule of practice, email addresses should be presented as LOWER CASE.
You can mix the case if you like BUT be careful. If your email system is case sensitive for usernames, you’ll need to take that into consideration.
Many companies utilize the mixed case email formats. There is an added usability feature in this option – it helps to separate firstnamelastname email formats:
When using separators like dots, hyphens or underscores, there is be no need for mixed case characters. For such emails addresses all lower case is suggested:
