Very helpful tool. I use the free tier and it covers the basics. Anyone worried about the recent permissions update: TLDR; nothing new as far as I can see.

Under Manifest V2 (v4.19), permissions and host access were lumped together under one simple umbrella.

Under Manifest V3 (v5.63), web browsers separate functional browser permissions (like saving your settings) from target host permissions (the actual websites the code can touch).

Because the code structure changed to the modern template, Firefox handles this as a permission change and forces a manual review, even though Keepa is still only targeting Amazon and Keepa domains to overlay its pricing graphs.