How to send emails to multiple recipients

How can I send an email to multiple recipients without all recipients seeing the entire list of email addresses of all the other recipients?

A bad idea is to use the field "TO" and to write all of the e-mail addresses in this field like that:

TO: recipient1@example.com; recipient2@example.com

This results in all recipients are able to see the addresses of all other recipients. Especially if we want to send a newsletter or similar circular emails to many recipients, we should avoid this.

First, every spammer would be happy about such a newsletter, because he gets a potentially significant number of e-mail addresses all at once and secondly, we run the risk to get our email itself put into the spam folder of the addressee, because the email program can think, that this is only another mass mail with this huge list of recipients.

The solution

The solution is called BCC (Blind Carbon Copy). In the normal field for the receiver, we write our own address (in the example me@example.com) and our list of recipients goes into the BCC field:

TO: me@example.com
CC:
BCC: recipient1@example.com; recipient2@example.com

All recipients in the BCC field remain invisible to all other recipients. Thus, each recipient only sees the address of the sender in the TO field and all other addresses remain unknown and we protect the data.

Why my address in the recipient field?

Now you may wonder why you should write your own e-mail address into the recipient field. You may think that this makes no sense, because you will get the mail with this yourself and you do not need to receive it after you have written it.

However, the problem is that, unfortunately, we have to specify at least one recipient. Otherwise our mail program complains. Of course, we could also just write one of the addresses from the recipient list into the "TO" field, but with this, at least one recipient would be no longer invisible to the others. Another solution would be to write just any address to the field, but that is no solution either, because the content of the mail should no be sent to someone at random.

Therefore, we take our own address. Because the recipients know this address anyway and we also already know the contents of the mail.

The correct delimiter

Outlook uses the semicolon as a separator between the email addresses. Other programs may use the comma. In general, even both delimiters can be taken equally and interchangeably.

If you don't know, you can just test it, which separator is working in your personal mail application.