If you're even a little bit computer literate, ignore the one star reviews. This is one of the most comprehensive add-ons that I've seen in Firefox. The bonus is that it also works on Chrome. Once updated, it works on Edge too! I used it for free for a long time before I realized that there are too many devices and too many browsers in my house to keep the updated list. I paid for it. I rarely pay for anything, so that's saying something. The cloud list periodically downloads itself back. It is obviously true that add-ons can be bypassed by a kid that knows how, but it's also true that Foxfilter lets you block the Firefox settings page and block it with a password. It is true that some of the default keywords are not very good (18, 21), but you can easily change them. I have my list published on 4bz.org, file name is FoxFilterList.zip

The best answer to keeping your kid safe is on the DNS of your router. Open DNS, Clean Browsing DNS, and others are good. You can use those for free on your router or on your phone service provider. For the keywords of the sites, Foxfilter is better. It's not really possible to name every website that might be needed, but getting the keywords in the title and meta data of the page does great. There's no perfect solution, but this one is good.

Awful add-on. There is no way to get rid of it and never blocks the right things. For example, once it blocked the word 'Essex' and multiple other times it blocked the word 'adults' in the sentence 'kids and adults alike will love this'.

Whenever an 'alert' pops up, it automatically switches all of your tabs to the website that it thought was 'dangerous'. Interrupted my workflow way too many times!

All filtering features are most certainly not free. You must pay to make an account to change any of them.

Useless even as a personal accountability tool, as the "fReE" version blocks non-adult websites for no reason.

I had this extension downloaded for less than 48 hours before I had to delete it.

Great supplement to LeechBlock NG for personal productivity and not getting caught up in the news, fandoms, rabbit holes through Wikipedia, etc.

Works out of the box!

So, in order to prevent my child from turning off this add-on, I have to put a password. In order to put a password, I have to pay.

I get that it's a great tool, and you're providing it for free, but it's kind of useless when the whole of it can be undone by a kid with enough time to poke around in the settings.

Thanks, but no thanks.

It was difficult to set up and difficult to remove. It filtered strange things, like the number 18. Why??!!! Yet some very filthy material came up several times.