hey @gianpaj. FCM and Ably Push Notifications are similar in that they both provided a unified API to communicate directly with APNs, and of course to Google's own native messaging APIs. The differences really lie in the fact that our push API is embedded within a broader set of realtime APIs for pub/sub streaming and messaging. So developers use Ably's data stream network to satisfy a broad set of realtime requirements, not just push notifications. The Ably SDKs, when instanced, establish a persistent multiplexed socket connection to the Ably service, and can subscribe to and publish streaming data from one or more channel, subscribe to or be present, handle encryption natively, etc. Push notifications are a neat feature for devs who want to additionally have access to a unified API for push notifications that can be used to wake their apps or show notifications to users who don't have the app open on mobile devices. Does that make sense?

@matthew_o_riordan Thanks for the quick reply! I haven't tried Ably SDKs for more than 6 months but I believe Channels is not ideal for building a "WhatsApp clone" as messages are deleted after 72 hours https://support.ably.io/support/... Sorry to change the topic. My use case is a built-in real-time chat (messages should persist for 3 months or more) and sending push notification for those users who are either not connected or didn't read the message (mobile app is opened on another screen). Would I have to build and maintain a server to work with the above logic? I've been willing to find a 3rd party solution can deal with this I don't have to keep polling every 5 seconds if a user has read or not chat message and then send a push notification via FCM, etc. Happy to move this to email or another medium. Thanks again

@gianpaj re: building a WhatsApp clone, Channels are a good fit for the distribution of messages, but not for long term storage. Long term storage is always domain specific, for example some people need to index by participants, text, metadata, time or ordering. We provide indexing by time and ordering, but not by any other indexes, and as such, we recommend using the Reactor (https://www.ably.io/reactor) to stream data into an appropriate system that can index and store for the longer term. In regards to Ably as a drop-in chat solution, you are right, we are intentionally a lower level pub/sub, streaming, interoperable and protocol agnostic API. We are not a chat-only solution, but are of course used by many chat providers for our robust messaging infrastructure. So if you are looking for a drop-in chat solution, I would say Ably is not for you. If you want a serverless pub/sub messaging & streaming layer in your stack that has the flexibility to scale well beyond just your chat requirements, so long as you build the UI and logic on top, then we're your best bet! Hope that helps. Feel free to reach out to me at www.ably.io/contact and I'll be happy to elaborate further.

@dpflucas this is still in our backlog. Sadly the demand has not been as great as we expected for this, hence why it's not been prioritised over other features at this stage. For other readers, see https://blog.ably.io/smart-notif... for the context of what Diogo is talking about. If you think this is a useful feature, please tell us here, and we'll definitely reconsider prioritisation.

@rafaelgfest6 it's true .NET and Go are not fully supported within the SDKS, however both support the flexible request method (see https://www.ably.io/documentatio...) which will allow you to use the push notification admin APIs now anyway with both of those SDKs. In terms of target support, we'll be adding .NET target support within the Xamarin platform at some point too. That's definitely on our roadmap, although will be prioritised based on user demand.