Data Privacy when using this mail merge solution
I’ve had a couple of people ask about privacy/security with this published solution and here is an explaination:
This solution uses Google Apps Script which is a scripting language that runs on Google servers https://www.google.com/script/start/
Apps Script can be used by developers to build 3rd party Add-ons for Docs, Sheets, Slides and Forms. There are add-ons for Google Sheets which can be used for mail merges https://gsuite.google.com/marketplace/search/mail%20merge
The mail merge in the solutions gallery is different in that it’s not shared as an add-on. Instead all the Apps Script code used for this application is attached to the copy of the Google Sheet you make in the setup instructions. The Apps Script code is attached to the copy of the Google Sheet and I as the original sheet owner don’t have access to either the copied Google Sheet or the copy of the Apps Script code attached to it.
In the copy of the solution you can see all the code by opening Tools > Script editor… I appreciate that not being a developer it might not make much sense hopefully it gives you some comfort to see the code that is being executed. A test you can do is make another copy (copy B) of the original copied solution (copy A). If you edit the code in the Script editor for copy A and save it, when you open copy B the script is unchanged (this means when you run this solution there is no way for me as a the original developer to change the code and do something malicious).
In terms of this solution and where the data goes, as Google Apps Script runs on Google servers it remains in your Google account, the script essential runs as if you were at the keyboard (see Script Authorisation docs https://developers.google.com/apps-script/guides/services/authorization). In terms of Apps Script additional terms these are also available from Google’s website https://developers.google.com/apps-script/terms.
The last couple of sentences are useful guidance “Using or importing any Script or Add-ons is at your own risk. You should only run the script if you trust the developer of the Script or Add-on, as you are solely responsible for any compromise or loss of data that may result from using this Script or Add-on.”
In terms of trustworthiness I would highlight the code is visible to you and with the experiment noted above hopefully it reassures you that once you make a copy of the solution only people with edit access to your copy of the sheet can change the code. This solution has also been published in the G Suite Solutions Gallery https://developers.google.com/gsuite/solutions/mail-merge. With this solution all the code is run on Google servers. Ultimately it is however up to you to decide whether you are happy to use this solution.