I also tested Boomerang on an i Phone 8 running i OS 11.0.
Although not many other services offer support for Amazon Fire tablets, device support for Amazon's cheap and kid-friendly device lineup would be a welcome addition.
The Geofences tab lets you set up location boundaries for your child and the Dictionaries section is where you create a database of words that your child is not permitted to use.
This lists all the words in language, so if your child happens to glance over your shoulder while you are making edits, their vocabulary could become quite colorful.
Android users, on the other hand, get but have to pay per year for each device protected. Kaspersky Safe Kids is .99 per year for unlimited child profiles and devices, and it covers PCs and Macs.
Apart from the basics, Boomerang also lets you construct geofences, monitor You Tube app activity, and set up always-allowed actions for emergencies.
Although the web interface is dated and it doesn't track social media activity, it could still be a solid choice if you only intend to monitor mobile devices.
You can set up restrictions and device rules from either the web interface or from the mobile app itself.
A few rules can be set on the web, but not in the mobile app, and vice versa.