Auto-CC is an extension for the Mozilla Thunderbird email client that can configure the email client to automatically send CC or BCC emails whenever an email is send from the program. The extension is currently experimental which means that users need to log into the Mozilla website before they can download and install the mail extension.

The email address that the messages are send to has to be configured in the Thunderbird Config Editor. The editor can be accessed by clicking on Tools > Options, selecting the Advanced tab and clicking on the Config Editor button. Adding the auto_cc filter will display four parameters of the Thunderbird extension.

• extensions.auto_cc.auto_cc_address: Double-click to enter the email address that will receive the CC or BCC emails.
• extensions.auto_cc.enabled: Auto-CC is enabled if set to true and disabled if set to false
• extensions.auto_cc.send_as_bcc: Will send the emails as BCC instead of CC if set to true.

A button can be added to the Compose toolbar to quickly turn the feature on or off. One thing that this extension is missing is the ability to select CC or BCC emails on an account basis. As of now all accounts are affected if the extension is enabled which might be ok in a work environment but not at home. The toolbar button is not the perfect solution because it quickly becomes an inconvenience to turn the extension or or off several times a day depending on the emails that are send out. It is also likely that the user will forget to turn on or off the extension from time to time.

As of now it’s a great solution for users who use Thunderbird in a work environment which requires to BCC or CC emails to another email address.

Update: Auto CC has been discontinued. Thunderbird 3 users can configure automatic CC and automatic BCC in the account settings of the individual email account. This is reached via Tools > Account Settings > Copies & Folders (of each account). Multiple email addresses can be added to Cc these email addresses and Bcc these email addresses.

The built-in feature is more powerful than what the add-on offered, as it is possible to enter multiple email recipients.