This is a really useful integration as is, though some suggestions on how to make it more versatile.
There seems to be 2 “color” data fields, “color” and “bkgcolor”, in which the first changes the color of the block the message is displayed on. The second “bkgcolor”, near as I can figure, doesn’t really do anything. What there isn’t is a data field for the color of the text. Is this feature a possibility? More text sizes would be nice too as even “max” isn’t very big, or even fonts, though I can see where that could get complicated pretty fast in that there is both an HA and and Android component to this. Text color on the other hand seem like it would be inherently doable, given that the block the text sits on can be changed. Also, what IS the font that is being used and is there anywhere you can see the full character set?
One other nice feature, that has been used in other notification apps, is to pass msg.topic to “title” and message.payload to “message” if those fields are null or unset. It would simplify automatons using this integration.