If you find yourself writing the same emails over and over again and wish you could schedule reminders and follow-ups, it may be time to set up auto-responses and scheduled emails. We'll show you how to do this in Mozilla Thunderbird, the cross-platform, free, and open source desktop email client.

Note: We've used the Windows version of Thunderbird. However, our instructions equally apply to the Mac and Linux versions, although the interface may differ slightly.

Auto-Response Filter

An auto-response filter lets you define filters for incoming emails and pair them with a template message. When an email triggers the filter, the sender will automatically receive a template response. Here are examples where an auto-responder can come in handy:

Now let's see how you can create an auto-response in Mozilla Thunderbird.

Set Up Your Message Template

To create your template, use the Menu Bar to go to File > New > Message or -- if you're using the Mail Toolbar -- click the Write button to start a new email or simply press the keyboard shortcut CTRL + N (Command + N on the Mac).

Next, compose the message as if you were writing an ordinary email. Remember to add a Subject!

Now save your message as a template. In the email's Menu Bar, go to File > Save As > Template. or -- within the Composition Toolbar -- expand the Save drop-down and click Template.

Write as many templates as you need, then proceed to create your filters.

Tip: If you cannot see any of the menus or toolbars mentioned above, right-click an empty spot of a visible toolbar to see which additional menus are available. Set a checkmark next to any toolbars you're missing to make them show up.

Set Up Your Message Filters

Back in your Thunderbird Menu Bar, go to Tools > Message Filters... to open the respective window.

In the Message Filters window, click the New... button to start setting up a new filter.

Note: If you use multiple email accounts in Thunderbird, be sure to set the email address your filter should apply to under Filters for.

Start by setting the Filter name. This should be something you can easily recognize, in case you need to edit your filter later.

Under Apply filter when, instruct Thunderbird when to run the filter. For example, if you'd prefer to see all mail before sending an automatic response, choose Manually Run. The advantage of running filters manually is that you can apply them to selected folders only. To filter all incoming mail, select Getting New Mail. Whether or not this is done before or after Junk Classification doesn't matter, unless you can't get Thunderbird to filter the body correctly; in that case, go with Filter after Junk Classification.

Note: You can also set filters to run when Archiving or After Sending emails, meaning you can use filters to organize your mail. For our auto-responder, these options are less interesting.

Now it's time to set your rules. First, decide whether the filter should Match all of the following or Match any of the following rules. Then compose your rules. The filter criteria can apply to anything from email subject to who was CCed and you can even create custom criteria. For our purpose, Subject and Body should suffice. Click the + icon to add additional rules. Clicking the -- button will delete the respective rule.

Note: You can also make Thunderbird Match all messages, which won't allow you to set any rules. This feature is useful if you need to bulk-process incoming email from a specific address (chosen in the first step). For example, you might have a spam email account and want to automatically delete all incoming email.

Finally, Thunderbird needs to know what to do with messages that match your rules. Under Perform these actions you can select Reply with Template, then choose your template. You can also set additional rules, such as moving the message to a specific folder.

When you're happy with your filter, click OK to save.

Tip: You can set up multiple stages of filters to work together. Below is a screenshot of all available filter criteria and actions. For example, you could set up automatic filters to move all incoming messages into folders, based on your rules, but without triggering an auto-response. Now you have time to double-check what's in those folders and move mail in and out of as needed. Finally, you can manually run various auto-response filters on specific folders.

Creating a Scheduled Email

Another unique feature that you can enable in Thunderbird is creating scheduled emails. It means Thunderbird will send those emails on a specific time in the future. This feature would be really useful to send reminders, either to yourself, your friends, or to groups of people.

Since this is not a default Thunderbird feature, we'll need to enlist an add-on called Send Later. This add-on is similar to Boomerang for Gmail, except that it's free and unlimited.

Setting Up Send Later

The easiest way to install a Thunderbird add-on is directly through the Add-ons Manager. Click the Thunderbird Menu icon (three vertical lines) and select Add-ons. In the Add-ons Manager, switch tot he Extensions tab. Locate the search box at the top right and search all add-ons for Send Later. Click Install next to your match.

Your add-on will download and install in one step. Click Restart now to complete the installation.

Before you head off to use the add-on, return to the Add-ons Manager > Extensions and open the Send Later Options. Here you can set up your Send Later preferences, including General settings, custom keyboard Shortcuts for different send delays, and Advanced options.

Tip: Select "Send" does "Send Later" if you want to be able to cancel a message you accidentally sent.

Using Send Later

Next time you've written an email you want to send later, go to File > Send Later or press CTRL + SHIFT + RETURN.

In the Send this email later window that pops up, set the day and time under Sent at, pick a Recur mode if you want this email to repeat, and choose one of the other options as needed.

Your Emails Under Control

These two features should help you keep your emails under control. They also highlight Thunderbird's big advantage over webmail clients: an extensive add-on repository that contains a solution for whatever you want to do.

How do you use filters and add-ons to organize your email in Thunderbird? Share your tricks and which add-ons you like best in the comments below!

Originally written by Jeffry Thurana on January 19, 2011.