Caju on your phone
Caju runs in the browser, but it can have its own icon just like any other app. It is quick, it takes almost no space, and you do not need an app store.
Opens without the browser bars, leaving more room for a child to tap.
The icon sits next to your other apps. Nobody has to type the address.
It is the same Caju, with the same profiles and everything you have set up. Nothing is lost.
iPhone and iPad
Five taps, in Safari.
The steps below are in Safari
Chrome on iPhone is very similar, only the menu sits elsewhere. What genuinely does not work is opening Caju inside Instagram, Facebook or WhatsApp: those apps use their own browser, which has no such option. Tap the three dots, choose “Open in Safari” and start there.

In the Safari bar at the bottom, to the right of the address.

It is the first option in the menu that opens.

It opens the full list of actions, at the end of the share sheet.

It is in the list that just opened, with a plus sign beside it.

You can keep the name Caju. Leave “Open as web app” on so it opens full screen.
That is it. From now on you open Caju from the icon, like any other app.
Android
The app is in closed testing. Two steps, done on your Android phone.
Do this on your Android phone
It will not work on a computer: while the app is in closed testing it has no page on the web store, so the link returns an error. And use the same Google account you are signed in with on the phone's Play Store, because test access is tied to the account you join the group with.

Open the group and tap “Join group”. That is what grants access to the test.
Join the group
Open the opt-in link, confirm you want to be a tester, then follow the link to Google Play to install.
Open the opt-in linkThat is it. Caju sits on your home screen as a Play Store app and picks up the test updates.
The ones that come up most often.
Create your account, then add the icon to your home screen. It takes under a minute.