Are domain names or email addresses "case sensitive"?

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When people send you email or visit your website, the addresses are not case-sensitive. They can be typed with any mix of capitalization.

For example, people can send email to “”, “”, or even “MYADDRESS@EXAMPLE.COM” — it’s all handled the same way by our system.

Similarly, people can visit “”, “” or “WWW.EXAMPLE.COM”, and they’ll see the same website.

So when you give your email or website address to another person, you (and they) can capitalize it any way at all.

... but some usernames should be all lowercase

Although other people can capitalize your email address and domain name any way they want, three places in our system allow you to use your email address or domain name as the “username” in a username and password combination that you enter into a program.

In these three places, the username must be entered as all lowercase:

Our instructions for each of those three situations clearly show that it needs to be all lowercase, so you don’t need to remember these — we’re just mentioning it for completeness.