Mailto.wiki gives you multiple options to change how e-mails are displayed in Confluence. These settings are available in the Formatting tab on the configuration page (see Getting Started).
E-mails often contain a styled HTML version to display in graphical e-mail clients and a plain text version for robots, screen readers and old school text only e-mail clients. You can set a preferred format in the Preferred Text Format setting. Then when e-mails contain an HTML and an alternative text version the right one is chosen.
For security reasons and to filter out broken code all HTML goes through an HTML filter. You can disallow and allow certain elements like images or links in the HTML Filters section. When you disallow all elements all HTML e-mails are basically converted to text-only e-mails.
Depending on the settings chosen your results may look very different. The following examples should help you to choose the right settings for your use case.
Currently, it is only possible to change the formatting for all e-mails. There is no mechanism to set different formatting rules for individual e-mails. If this is important to you or you have any other suggestions for improvements, please open a ticket in our service desk. We are always interested in feedback from our customers.
Example 1 - HTML e-mails
The default setting is to prefer HTML over plaint text and to allow all safe HTML tags.
If you send an e-mail containing HTML with these settings, it will be displayed similarly in Confluence. Complex HTML mails like newsletters might not always look 100% correct in Confluence. But usually everything should be readable without issues. If your e-mails uses tables to format content, you might experience unwanted small white borders around table cells. We are aware of this issue but unfortunately there isn't really anything we can do about that without also risking breaking functionality of Confluence.
Congratulations, now you know how your e-mails are displayed and how to set which format to prefer.