知识点滴 - Email地址不区分大小写

电子邮件地址本身对字符大小写不敏感。这意味着实际的电子邮件地址，如 "[e-mail]"，并不区分字母的大小写。无论你输入的是大写字母还是小写字母，它仍然会到达同一个电子邮件账户。例如，如果您的电子邮件地址是 "[e-mail]"，但有人输入的却是全小写字母，那么它仍然会被正确发送。不过，值得注意的是，"@"符号之前的部分，即本地部分，有时会因主机系统的不同而区分大小写。但实际上，大多数电子邮件系统都将本地部分视为不区分大小写。因此，一般来说，在发送或接收电子邮件时，不必担心电子邮件地址的大小写敏感性。

电子邮件地址的用户名，不建议使用的字符： & = _ ‘ - + 。因为有些邮件服务器不一定支持这些特殊字符。还有一些英文之外的字母，比如拉丁字符，也不一定支持。

有些电子邮件地址名可以使用dot字符。比如[e-mail]。

Email addresses themselves are not character sensitive. This means that the actual email address, such as "[e-mail]", doesn't care about the case of the letters. Whether you type it in uppercase or lowercase, it will still reach the same email account. For example, if your email address is "[e-mail]" but someone enters it in all lowercase letters, it will still be delivered correctly. However, it's worth noting that the part before the "@" symbol, referred to as the local part, can sometimes be case-sensitive depending on the host system. But in practical terms, most email systems treat the local part as case-insensitive. So, in general, you don't need to worry about the case sensitivity of email addresses when sending or receiving emails.

扩展阅读：

1，Email地址区分大小写吗

Are Email Addresses Case Sensitive? And Other Email Best Practices | Mailchimp