We are working on personalizations on each and every aspect of user interaction and want to send personalized push notifications to the users, meaning each user will receive different notification personalized to him.
We are currently using Onesignal, So can I use Onesignal to send personalized notification upto over then a million user base ? Or I have to migrate to some other alternatives, if so please suggest some reliable solutions.
OneSignal can certainly be used to send personalized notifications to each user.
To implement this you will need to call the OneSignal API for each user that you are sending the notification to. Since this might take a while to send to 1 million devices, you can parallelize your API calls to do it faster.
Note that you should not make more than 20 requests per second though, since OneSignal's API may throttle requests from the same API that exceed this limit.
来源：https://stackoverflow.com/questions/40083914/sending-personalized-push-notifications-using-onesignal