Easily review content
For management, translation and programmers, each transactional email has a dedicated link, which loads the appropriate templates with placeholder data and builds the final HTML that will be sent to the user. This allows everyone to easily review the content and confirm/fine-tune each email.
Those emails are listed on directory view, grouping emails by purpose, with a language switch to display each version.
The whole setup simplified the translation a lot, since we only had to extract the placeholder content to a Excel table and let the translation take it from here.
Documentation for designers and programmers
As we laid the groundwork for our emails, I did extensive research on email coding to get up-to-date with the best practices, so our content displays correctly in every major email client. These best practices were documented and applied in the templates.
We used TWIG templates to simplify the markup and help us design emails really fast.
We were able to abstract everything using TWIG includes, removing the complexity of the HTML and CSS mess that is required when designing retro-compatible emails.