JavaScript PushManager register() Method

What You’ll Learn

PushManager.register() is a deprecated, non-standard instance method that requested a new push notification endpoint URL via a DOMRequest. Learn what it did, why MDN replaced it with subscribe(), how to feature-detect it, and modern migration patterns—with five examples and try-it labs.

Introduction

To send web push messages, your app needs an endpoint the push server can target. Early Mozilla push drafts exposed register() on PushManager to obtain that endpoint as a plain URL string.

MDN now marks it deprecated and non-standard. The standardized replacement is subscribe(), which returns a full PushSubscription object with endpoint URL and encryption keys. Modern PWAs should never call register() in new code.

Understanding register()

A legacy instance method on PushManager that asked the system to create a new push endpoint.

• Parameters — none.
• Returns — DOMRequest (not a Promise).
• Success result — endpoint URL string.
• Errors — handle via req.onerror.
• Cleanup — MDN pairs with unregister() when done.
• Superseded by — subscribe() (Baseline Widely available).
• Available in Web Workers per MDN (where still supported).

📝 Syntax

pushManager.register()

Return value

A DOMRequest object. On success, req.result is the endpoint URL string.

MDN legacy pattern

// Legacy — do not use in new code (MDN sample used navigator.push)
const req = navigator.push.register();

req.onsuccess = () => {
  const endpoint = req.result;
  console.log(`New endpoint: ${endpoint}`);
};

req.onerror = (e) => {
  console.error(`Error getting a new endpoint: ${e.error}`);
};

⚖️ register() vs Modern APIs

Examples Gallery

Examples explain legacy register() and show modern subscribe() replacements. Use View Output or Try It Yourself.

// MDN sample — navigator.push in very old Mozilla code
const req = navigator.push.register();

req.onsuccess = () => {
  const endpoint = req.result;
  console.log(`New endpoint: ${endpoint}`);
};

req.onerror = (e) => {
  console.error(`Error getting a new endpoint: ${e.error}`);
};

New endpoint: https://push.example.com/…

function legacyRegister(pushManager) {
  if (typeof pushManager.register === "function") {
    return pushManager.register();
  }
  if (navigator.push && typeof navigator.push.register === "function") {
    return navigator.push.register();
  }
  return null; // not supported — use subscribe()
}

null — register not supported, use subscribe()

const req = pushManager.register();

req.onsuccess = () => {
  sendEndpointToServer(req.result);
};

req.onerror = (event) => {
  console.error("Push register failed:", event.target.error);
  showPushUnavailableMessage();
};

Push register failed: NotSupportedError

const registration = await navigator.serviceWorker.ready;

const subscription = await registration.pushManager.subscribe({
  userVisibleOnly: true,
  applicationServerKey: urlBase64ToUint8Array(VAPID_PUBLIC_KEY),
});

// Full PushSubscription — endpoint + keys (not just a URL string)
console.log(subscription.endpoint);
await sendSubscriptionToServer(subscription);

https://fcm.googleapis.com/fcm/send/…

const registration = await navigator.serviceWorker.ready;
const pm = registration.pushManager;

const permission = await pm.permissionState({ userVisibleOnly: true });
if (permission === "denied") return;

let subscription = await pm.getSubscription();
if (!subscription) {
  subscription = await pm.subscribe({
    userVisibleOnly: true,
    applicationServerKey: vapidKey,
  });
}

console.log("Ready:", subscription.endpoint);

Ready: https://fcm.googleapis.com/fcm/send/…

🚀 Common Use Cases (Historical)

• Reading old Mozilla push tutorials that call register().
• Maintaining legacy Firefox OS apps with navigator.push.
• Understanding why subscribe() returns more than a URL.
• Migrating endpoint-only code to full PushSubscription objects.
• Teaching the difference between register and getSubscription().

🔧 How It Works

📝 Notes

• Deprecated & non-standard on MDN—not for new production code.
• Superseded by subscribe() (Baseline Widely available).
• Not Experimental — it was Mozilla-specific and removed from specs.
• DOMRequest — callback-based; unlike modern Promise APIs.
• Pair with unregister() — MDN recommends cleanup when endpoint no longer needed.
• Related learning: getSubscription(), permissionState(), navigator.serviceWorker, JavaScript hub.

💡 Best Practices