The simple answer is probably Google Docs with all the tracking and collaboration turned on so that every change is tracked by who made it and when. But again, that's only relevant for the text and maybe minimal layout.
Staff get to format the email in a graphical editor they’re familiar with that handles revisions etc, and we don’t need to manually import templates.
It had a great intuitive UI to track diffs in prose that everyone and anyone could understand. (Truly exceptional and generous work Nate! Made my life better! Thank you!)
Otherwise I used Mailtrain with a small team and it worked ok. We used git for source code tracking for the designers and then the CMS for small changes.
i ended up showing them how to use github and create prs with a csv. at first i copy pasted the csv and imported it, but in the end completely automated it
it may seem completely alien to them at first, but if can get them access to a repo and just show them how to edit a file in the ui, it's much easier to do that and create a pr than it used to be in github. to me it was worth the initial headache - after a few weeks they were very smooth with it and changes got through way faster
It sends you summarized changes straight into inbox and it has a free tier.
If you do give it a try, I'd love to know what you think
Cheers!
What is your budget?
It will determine your options.
You can also do this yourself with something like Playwright: https://playwright.dev/docs/test-snapshots
For email templates, they usually create a HTML version hosted online somewhere too, don't they? You can probably use the same tools for those if they're publicly accessible.