I realized that Google Cloud Message is not reliable. Sometimes I lose messages. Sometimes I get a huge delay on message delivery.
I made some research and discovered Facebook and Whatsapp don’t uses GCM. Instead they implement they own push notification gateways based on sockets.
Is there an reliable alternative to GCM which I can use which Ionic 2?
Hi… yeah, it’s true they use their own notification service called MQTT with topic-based notification. You can roll up you own server. If you don’t mind forking out some money, you can use hivemq. It’s easy to setup and reliable with good support. But, if you want to go for open source, you may try a bunch out there. I have tried working with emqtt (erlang mqtt) and it was great. Easy installation, configuration, and provide clustering for scaling purpose.
The downside? Please create an ionic plugin for us 
I would suggest paho mqtt for java and cocoa mqqt for ios running on swift
Another downside? Although it may be tempting to roll up your own notification server, be remind that the cost is not something to be taken for granted. If you’re still working on your project, try to work around the issue and understand what push really is. Perhaps you can modify your business requirement to not rely on something like push for crucial stuff. Push is not actually made for that. The sooner your realize this, the better. Good luck!!
GCM can be made more reliable by specifying the priority and by increasing the GCM heartbeat so that the device doesn’t lose the connection to the gcm server. Also giving it a time_to_live of 0 ensures that gcm does it’s best to send the message now or never.
Also there is an alternative in pushy, which did send the notifications immediately when the app was in the foreground and background, but if the user swipes the app closed then the notifications were delayed like gcm. Pushy also charges per device.
Pushy founder here. Our SDK reconnects immediately when your app is swiped away from the recent apps list, so you shouldn’t have experienced this behavior.
You can definitely utilize our platform to improve your notification delivery rates.
When i evaluated pushy a while back, It worked flawlessly until i swiped the app closed, then many times it didn’t reconnect immediately and since i specified a time_to_live of 0, i wouldn’t receive the notification at all. This was only tested on a moto g phone, so it might have been a phone issue.
I’ve tested in a Nexus 4 too.
Depends how long ago you tested, since this issue was fixed in v1.0.10 of the Pushy Android SDK.
Try swiping our demo app away and sending a notification to it:
https://pushy.me/docs/resources/demo
I highly recommend trying again, and if you still somehow experience this issue, get in touch with our support which will be happy to investigate and fix the issue.