I've been using in the last few years. It's easy to use, easy to modify, feature-rich, and lightweight.

Best

The only extension I found where I can enable automatic translate upon selecting text (without displaying the button). Thank you very much for your great work!

good

好用

excellent

Good

The best FF translator add-on, thank you👍🏻

this extension is very powerful, but there's a feature at this era for Simple Translate have to implement, is that supporting extension itself in Sidebar mode! Firefox now support Sidebar, anyway if Simple Translate support Sidebar mode, it would be more awesome! sometimes I use translator in a short time, but for some moments, I want them to stay there longer!

OK.