I found this add-on, "Smart Amazon Smile" to be better than one of the alternatives, "Amazon Smile Redirect", because this add-on takes you immediately to smile.amazon.com, whereas "Amazon Smile Redirect" takes you to www.amazon.com, then a few seconds later forwards you to smile.amazon.com.

Of all the four "smart" redirect add-ons I tested, this is the only one that worked for me with amazon.de
I reviewed the downloaded source code today (not just from GitHub). No issues.

I'd removed a competing extension a few years back, because it made it so I couldn't browse Amazon while signed out. This extension fixes that problem perfectly, and makes it so that I actually remember to check out on Amazon Smile.

Works as expected. The best part is that this add on does not redirect when you are not logged into amazon which other similar add ons force you to do before continuing.

I frequently search Amazon, or just go there, through the search bar, and have occasionally bought things forgetting to use Smile. Works great, thanks!

Works perfectly every time. Seamless and instant.

Does what it says.

Doesn't cause redirection loops when not logged in, very useful!