Won't recognise my login details.

Doesn't work. Clicking "options" refuses to open inside Firefox settings and redirects to some external site. Useless.

Not installed on Firefox for Android

Doesn't work for Amazon Australia despite requiring that permission

The page says no account needed, but it seems they make the extension unusable without one. I just installed the add-on, and I clicked the Keepa button while looking at a product on Amazon. Instead of getting any price history, I get a complaint that I'm not logged in. Not very helpful at all.

Please import .au domain... your addon is great otherwise but I cannot use.

Add-on uses your device to scrape Amazon pricing data every 5-6 minutes or so, while obscuring the fact that it does this in a settings page and mentioning it nowhere else. This can be disabled by going to Manage Extension, clicking Options, then disabling "Allow the add-on to gather Amazon prices to improve our price data"

it doesn't support amazon eg

I don't get it, it just isn't working, absolutely nothing, I clicked the extension, the website won't load. Is there something needed to be done to use it?

Too annoying "Accept functional cookies" page which opens every time I visit amazon, nevertheless I've clicked "Do not add cookies" each time.

Needs an account (for no reason)

Wymaga założenia jakiegoś konta, nie pokazuje historii cen jak jest w opisie.

I've been using keepa.com for years and really like it, but the add-on doesn't appear to work, at least out of the box. Reading some comments it seems I might need to lower some security feature for it to function but none of the things I tried worked.
If the add-on needs extra steps to actually work, that should be mentioned on its front page and/or app settings!
Also, I'd expect at least clicking the add-on icon while I'm on a product page would go to Keepa's pricing history on that product at least, but it just loads my tracking list.
So, right now, the add-on has no use at all for me, unfortunately.

They claim that they support amazon.com.br, but they don't! Fake news.
The first message you get is: "Keepa can sadly no longer update product data for Amazon.com.br"