How do push notifications work in a React Native app?

Push delivery is a chain: the OS push service reaches the device, the app receives the payload, and your code decides whether to display, update state or navigate. React Native libraries wrap the native APIs, but the token and permission lifecycle is still yours to manage.

import * as Notifications from "expo-notifications";

export async function registerForPush(projectId: string) {
  const permission = await Notifications.requestPermissionsAsync();

  if (!permission.granted) {
    return null;
  }

  const token = await Notifications.getExpoPushTokenAsync({ projectId });
  await fetch("https://api.example.com/devices", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ token: token.data, platform: "mobile" }),
  });

  return token.data;
}

Lifecycle details that break in production

• Tokens rotate; re-register on every launch and replace the old token server-side
• Foreground notifications need an explicit handler to display or suppress them
• Taps must be handled for cold start, background and foreground launches
• Android channels control importance and sound; create them deliberately
• Remove tokens on logout so the next user does not receive the previous user's pushes

Notification payloads should be small and contain an identifier, not the full data model. Fetch the current record when the user opens the notification so the screen shows fresh data rather than a stale snapshot.