Push notifications

wikipedia:Push notifications (2009?)

• Apple Push Notification service (APNs): APNs auth key
• Firebase Cloud Messaging (FCM)

Related

• OneSignal (2014)
• Intercom (2011)
• Provisional push notifications (IOS 12, 2018) or asking permissions to use notifications
• Pushover

See also

• Push Notifications, Apple Push Notification service (APNs), APNs auth key, Token-Based Connection
• Push Notifications, Apple Push Notification service (APNs), Firebase Cloud Messaging (FCM), Certificate Signing Request (CSR)

https://developer.apple.com/documentation/usernotifications/asking_permission_to_use_notifications