Using Thunderbird for “Send Only” Email

Exactly 10 years ago today, I wrote Use Mailsmith to create a “send-only” email account for TUAW (which was later ‘replaced’ by Engadget).

Unfortunately, Mailsmith did not make the 64-bit transition, and another app known as “Let.ter” seems to have disappeared (although last time I checked, it did still work, but I don’t think it integrated with the macOS address book).

If you use Gmail (or “Google Suite” or whatever it is called), you can use a link like this to send email without ever seeing your Inbox:

https://mail.google.com/mail/u/?authuser=example@gmail.com&view=cm

Obviously replace example@gmail.com with your actual email address. That link will bring up a ‘Compose’ window, which you can use as normal, and then when you send the email, you will be left with a Gmail window which is basically inert.

However, I wanted a Mac app for this. More specifically, I wanted an app which would be able to autocomplete from my macOS Contacts..

It turns out to be much harder than you might think.

Most email apps think they are doing exactly what users want by making sure that they retrieve email as effortlessly as possible. Let’s be honest, that’s a reasonable assumption.

My first attempt was to set up an email app that I don’t usually use, and then either change or delete the IMAP information, so that the app could not download email.

Most email apps will freak out if you do this. First off, most of them won’t even let you delete the IMAP information, and if it is incorrect, they will continually throw error messages as you. Again, it’s a reasonable assumption that users will want to download email, so I can’t really fault them for this, but I found that it was extremely frustrating to deal with the error messages.

Recently, I decided to try this again, and found that it was actually possible to do. It’s not 100% as “clean” as I would like, but it works well enough, and until I find something better, this is what I will be using.

Thunderbird Swoops In

Thunderbird is the mail app from Mozilla, the people who make the Firefox web browser. I had tried this a few years ago and couldn’t get it to work, but it struck me as the email app that was most likely to allow this level of customization.

A search for “Thunderbird Send Only” led me to this post on Superuser:

A Thunderbird account is only for receiving mail. It cannot send mail at all.

To send mail in Thunderbird, you use an identity, not an account. Unfortunately, Thunderbird’s user interface makes the relationship between accounts and identities confusing, as the “Manage Identities” button is found within Account Settings.

Add an identity to your default account, and if necessary add a separate SMTP server for the new identity, but don’t otherwise configure the account. The new identity can send mail independently of the account, and it will never try to receive mail.

I also came across forum post from January 3rd, 2009 (!) saying essentially the same thing, so I decided to give it at shot. Apparently this has been possible for a lot longer than I realized.

The Thunderbird distinction between Identity and Account is important, so I will try to use both terms very carefully from here on.

Here’s the Downside

As far as I can tell, in order to set this up, you have to give Thunderbird access to a “real” email account to create the Account.

You can set this account to not download email automatically at launch, and not to download email periodically, but if you click on the ‘Inbox’ it will download email in the inbox, so that makes it a “No Go” as far as being a 100% reliable “send only” account for that email account.

However, I have an old Gmail account which I pretty much never use, which gets almost no email (even spam!). I created it for a project or something which never went anywhere. So it’s a good Gmail account to use to set up the Thunderbird account because even if it did download email, and even if there was email for it to download, there would be nothing in there to distract me.

You could even set up a new Gmail account and create a Gmail filter to automatically delete all incoming email. But I had this one already, so I decided to use it.

If you don’t have a spare email account, creating a new Gmail account is a bit of a hassle, but, IMO, worth it.

Here’s How to Do It

Step 1: Set up a new account in Thunderbird using an existing email account. This is not the email address you want to use for “Send Only” but another “dummy” account.

Step 2: Once you have it setup, click on the very top level (see screenshot above, item #1), and then choose “Account Settings” (item #2).

Thunderbird 001 Click On Account Settings

Step 3: Click on “Manage Identities” at the bottom right corner.

Thunderbird 002 Manage Identities

Step 4: Click to Add a New Identity

Thunderbird 003 Identities Add

Step 5: Fill Out Information. Items 5, 6, 7, and 8 are the only ones that are required (as far as I can tell.) #8 may not be required, but it’s definitely something I recommend. This should be the account you want to use as “Send Only”.

Thunderbird 004 Fill Out Identity

Don’t click “OK” yet – click on #7 to create a new SMTP server. This is a vital step!

Step 6: Enter SMTP Server Information. This is the information for the “Send Only” account.

Thunderbird 005 STMP Info

Note that I have given the “Description” (item #9) to make it obvious that this is the SMTP server I want to use when using it as “Send Only”.

Items 10-14 will differ, depending on the options for “Connection Security” and “Authentication Method” that you will have to choose for your email provider. What is shown here is for Gmail, but if you use another email provider, it may be different. (If email does not send, or does not send from the proper account, remember this step, because this is probably where you will need to come back to.)

Step 7: Set Default Identity.

Click the “Manage Identities” button again (see Step 3) and you should have two Identities now. Either choose the one you want to use as “Send Only” and click “Set Default” or click the one you aren’t going to use and click “Delete”.

Thunderbird 007 Default Identity

You can see above that I’ve already deleted the one I’m not planning to use.

Step 8: Set the Outgoing Server (SMTP).

Thunderbird 006 Default STMP Server

Click the next to #15 and change it to the “Send Only SMTP Server” that we created in Step #6. I wish I could delete the other SMTP server, but I cannot find a way to do that. Let me know if I missed it.

Step 8: Send a Test Message.

  • Close the “Tab” with the account settings.
  • ⌘N to open a new “Compose” window.
  • Check the “From” address is the correct one (if not, go back to Step 7).
  • Send a test email to yourself. If you set up a Gmail SMTP server, the first time you send a message Thunderbird will open a browser window to authenticate you with your Gmail account. Once you’ve done that once, you won’t need to do it again.

There Is No Step 9. Hopefully.

I hope that will work for you. If not, let me know. It can be a bit of a challenge writing up instructions after the fact because I’m always afraid I will forget some detail or some step that I did the first time through.

If you want to discuss this, please post to this thread on the Mac Power Users forum.


Optional Steps

  • in “Account Settings” click on “Server Settings” and uncheck the boxes next to “Check for new messages at startup” and “Check for new messages every X minutes” and “Allow immediate server notifications when new messages arrive.” This should prevent Thunderbird from automatically downloading email from your the email account we setup in Step 1.
  • in “Account Settings” click on “Copies & Folders” and choose options for where you want copies of sent messages to be stored. You may want to set it up to automatically BCC yourself at the “Send Only” account so you’ll have a record of those emails in that account. (Note: if you use Gmail for SMTP, it will automatically store the message in your Sent email ‘folder’ on Gmail, so you don’t need to do that for Gmail.)