I want to do email merge (i.e. send emails by taking input from a spreadsheet) from a python program. I have looked into python's email module, but that requires storing password etc in the code which is not feasible. My plan was that i could call an thunderbird's mail merge plugins from my python program. This way, there would be no problem for credentials. The email merge plugin used is this: Mail Merge 9.6.1 (by Alexander Bergmann) https://addons.thunderbird.net/addon/mail-merge/ i _think_ it would require knowing the CLI command. On looking for "thunderbird CLI" online, I found this article: [http://kb.mozillazine.org/Command_line_arguments_-_Thunderbird Command line arguments - Thunderbird] which showed following sample command to launch a new thunderbird compose window `thunderbird -compose "to='john@example.com,kathy@example.com',cc='britney@example.com',subject='dinner',body='How about dinner tonight?',attachment='C:\temp\info.doc,C:\temp\food.doc'"` This is good for composing single mails! But how to specify the arguments for the mail merge? Being dependent on the add-on, i know that this is not a thunderbird's issue per se, but i couldn't find any other way to find about it. Thanks.