[hendrikmans]

I'm assuming you're talking about Apple Push Notification Service.

Chatto so far commits to a fully fleshed out PWA experience. Push Notifications are delivered through Web Push (and Apple's Declarative Web Push additions). Web Push uses the browser vendors' own push gateways.

There are some missing bits currently in Chatto's multi-server story; when you add another server within the UI, its push notifications won't work because the other server can't make its service worker known to your device. One of the next versions of Chatto will improve this significantly, eg. with Chatto servers being able to act as push relays for others.

Eventually there's going to be mobile apps operated and provided by ChattoCorp, who will also set up and pay for the required push services.