Any number of e-mail addresses - even without aliases

Our servers support so-called "mail extensions". Separated by a plus sign, you can change the local part of your user name (everything before the @) by any number of extensions. The "extensions" are ignored by our mail servers (when they are placed in mailboxes), so that e-mails are still assigned to the original e-mail address.
In addition to your e-mail address me@mailbox.org, you can also receive e-mails addressed to me+test@mailbox.org or me+rssfeed@mailbox.org, for example.

Organize e-mails with mail extensions

All email addresses with these "extensions" are usually stored in your inbox folder. However, if there is an (IMAP) folder with the same name (in our example "test" or "rssfeed"), then the e-mail is automatically sorted into this subfolder without you having to create an extra filter rule.

Please note:

  • the corresponding IMAP folder must exist, when the e-mail arrives
  • the name of the IMAP folder must not contain uppercase letters
  • "Mail extensions" are not usable as sender addresses for answering. For doing so, you need to use an e-mail client (like Thunderbird). There you can use mail extensions (like aliases) as sender addresses.

So, for instance, you can subscribe to your favoured newsletter with me+newslettername@mailbox.org and then create an IMAP folder "newslettername".

More advantages of mail extensions

Using "mail extensions" has more advantages than only sorting messages in folders.
If you suddenly receive SPAM or unsolicited advertising via an e-mail address with extension that you have only used for a page or a newsletter, you will immediately know who passed on your addresses.
Further you can individually mark an address e.g. with the communication with companies or suspect receivers by the extension of the E-Mail addresses, e.g. by me+company@mailbox.org. If you don't want to be reachable via this e-mail address later on, you can block the receipt of exactly this variant at any time by using a filter rule.


So you have the following advantages by using "mail extensions":

  • You can use the "extensions" with websites or for unknown persons as disposable addresses.
  • You can track, who gives your address to other persons/companies.
  • You can use them to organize newsletters, confirmation messages and more without creating filter rules.
  • You can keep your inbox clean and you can separate you e-mails by an easy way.
  • Last but not least: "extensions" are not aliases - and so they are usable with any mailbox-org plan - unlimited and free of charge.


Is it possible to use "multiple extensions", for instance firstname.lastname+shopping+company@mailbox.org?

Yes, our servers will look for the first "+" sign. All following characters (until the @) will be interpreted as the extension. So, every e-mail to the base address will be delivered. Please note: To get the messages delivered to the right folder, it needs to be named "shopping+company" in our example.

Can I user extensions with aliases, instead of the main address only?

Mail extensions will also work with aliases.