Activated for all websites by default. You can exclude website one by one.
So, If you don't want Grammarly injected on every page/site and all your typing sent.
There's no option to deactivate by default and activate for only a few websites.
Probably no GRPD compliant.

Sadly, I have attempted to use this plugin twice. Both times the plugin demands I sign up their site and nothing ever happens. The only thing the extension does is have a login button that redirects to the site if I am logged in or not. What a shame. Even if I am doing something wrong, it only allows me one option. To edit my work on their site. Which I wasn't really needing to do. So, 1 star.

Load of stuff, but it actually doesn't do a thing. In Disqus message boards it's doing nothing

ever since the program needed to be fucking updated it refuses to work for me and only leads me to blank pages

when I paste my 14.5 KB html code on the online site, it's hang my firefox, firefox say disable all extension, Don't do your magic when I paste a long text, I didn't want grammarly to look at 14.5 KB text.

Functionality is intermittent. Suggested corrections are sometimes incorrect or inappropriate. It occasionally freezes and locks out webpage navigation (typicially the text "edit in grammarly" appears somewhere on the screen when this occurs), forcing the closure and restart of the browser to resume activity.

I keep on downloading it in my system and it keep keep removing itself from my computer.

Uses too much ram. Its nearly impossible to use it on outlook. There is too much emphasis on UI and very little attention is paid to UX.

Not work with new edition gmail on firefox- but it works in chorme

Grammarly goes offline often to try to get you to buy the app.That is predatory activity.

I am trying to use this in Facebook; when it is there it works fine, problem is it isn't always there. Anyone know of a good alternative?

It is constantly stopping and refusing to work. When it works, it's good but those times are few and far between. I've had it with having to constantly reload it!

I'm using Windows 10 with Firefox 62.0.3 (64-bit).

... didn't work in Firefox at all.

It's confusing. I have installed the extension, now it says I should create an account and log in. So I've done that. Now it says I have to download another app. I don't want to install anything from someone I don't trust. So I can't activate it unless I download software, or am I just missing something? It I have to download something, why doesn't it say this, why does it only say I have to create and account and log in. Very confused.

Once you use it (by copy pasting my text into their website as it's not really an extension (if so it doesn't work on the text field where I'm testing it)), you be teased with improvements you have to pay to see. And the price is 30 $ a month. This wasn't communicated at all when I signed up.

I find all of this very deceptive. Why not be upfront about all the steps you need to take, and the price you need to pay, in order to use this comfortably. As a free extensions, this is pretty bad.

Doesn't work anymore

Uses 500MB of memory and slows down firefox. Not worth it.

This add-on makes Firefox slow at every web page.