Choosing a notification route

For ordinary mobile notifications, start with the platform-standard push route. The application server, data, authentication, and notification decisions may remain self-hosted; only delivery to the device is delegated to FCM or APNs. Push requires coordinated permission, registration, server handoff, receive, and removal stages; read the Push workflow guide before implementing it.

Standard route
  → Android: FCM
  → iPhone: APNs
  → iPhone VoIP: APNs PushKit, then CallKit and the call connection
  → Browser: FCM Web or standards-based Web Push after user permission

Delayed delivery is sufficient
  → Android / iPhone: Background Runner checks your HTTPS endpoint

Google-independent Android realtime is required
  → Foreground Service keeps a WebSocket to your server
  → requires an ongoing notification; no general-purpose iPhone equivalent

Comparison

Route	Timing	Platform	Sercrod surface
FCM / APNs	Standard timely mobile push	Android / iPhone	`*push`
FCM Web / Web Push	Opt-in browser push	Supported browsers; Home Screen web app on iPhone/iPad	`*push`
Background Runner	Delayed and OS-scheduled alternative	Android / iPhone	`*background-notification`
Foreground Service + WebSocket	Google-independent realtime alternative	Android only	`*foreground-notification`

Background Runner is not continuously resident and is not a complete push replacement. Android Foreground Service requires an ongoing system notification. iPhone does not permit an app to reproduce that general-purpose always-on route; even VoIP wake-up uses APNs PushKit.

Responsibility and costs

Sercrod supplies client adapters and directives. With standard push, the developer can keep the application backend self-hosted and use FCM/APNs only for device delivery. The developer owns authentication, provider credentials, token storage, recipients, deduplication, hosting, and distribution compliance. Never place server send keys in the app bundle.

FCM is listed as a no-cost product; surrounding Google services are optional and can be charged separately.
Self-hosting the application server still has server, domain, TLS, bandwidth, and monitoring costs.
APNs access and iPhone distribution are tied to Apple's current developer-program terms.
Android Foreground Service use must satisfy Android and store policy; it is an alternative, not the standard recommendation.