right now radar.chat is only available for android mobile devices:
The website shows it's in the Apple App Store now.
Radar.Chat claims that everything is self-custodial and if you lose your seed, you lose your bitcoin. They have no way to recover anything, is what they say. But at the same time, the idea was to make the app as simple as possible. Users aren't managing the channels or the liquidity. Radar.Chat owns the nodes and take care of everything in the background. It's worth asking what would happen if all that infrastructure fails and gets wrecked? So it's probably not as self-custodial as managing your own lightning node. Feels weird saying that. Something either is or isn't (self) custodial. There is no middle.
If all you need to recover the channel state is a seed phrase, I don't think it's really self-custody. That's not necessarily a bad thing, but if it is, they should say so. I've never really liked LN in self-custody. The fact that you need to create a backup after each transaction is just annoying. There's always a potential point of failure.
Some details on their homepage really confuse me. It currently don't have FAQ section that cover common question such as how to backup and restore the wallet and LN channel.
I've seen that on many projects: they don't offer details, they don't tell you how it really works, but apparently that's what the average internet user wants: just install something without knowing what it does.
No switching apps. No copy-paste. Just open a chat and send
Byteball had this almost 10 years ago already, on an altcoin.