# Send notifications

> Ask at the right moment, remember who said yes, send from your server, and open the right screen when a notification is tapped. From the Lia developer docs: https://docs.lialabs.org/guides/send-notifications

## 1. Ask when it helps

```js title="game.js"
async function waitForOpponent(room) {
  if (!Lia.notificationsAllowed) {
    try {
      const { allowed } = await Lia.requestNotifications();
      if (allowed) await api("/api/notify-me", { allowed: true });
    } catch (error) {
      // "notifications_off": your app can't send them; carry on without.
    }
  }
  showWaiting(room);
}

// They can also turn them on or off from your app's ⋯ menu.
Lia.on("notificationsChanged", function (data) {
  api("/api/notify-me", { allowed: data.allowed });
});
```

Lia doesn't tell your server when someone allows notifications, so tell it yourself, as above. Or keep it simpler: send when you have something to say, and treat `not_allowed` as a "no".

## 2. Send from your server

```js title="server.js"
async function notify(playerId, text, startParam) {
  try {
    return await lia("POST", "/notifications", { playerId, text, startParam });
  } catch (error) {
    const code = error.data?.error;
    if (code === "not_allowed") return db.setNotify(playerId, false); // they said no or stopped
    if (code === "rate_limited") return db.retryLater(playerId, error.data.retryAt); // retryAt may be missing
    if (code === "bad_text") console.warn("Lia refused the text:", error.data.problem);
    throw error;
  }
}

await notify(opponent, "@amara played. Your move.", "room-a81c2e09f4");
```

## 3. Open the right screen

```js
function route(startParam) {
  if (startParam?.startsWith("room-")) openRoom(startParam);
}
Lia.init().then(function () { route(Lia.startParam); Lia.ready(); });
Lia.on("startParam", function (data) { route(data.startParam); });
```

## Writing them

- **Up to 180 characters**, one line. Lia shows it under your app's name, so don't start with it.
- **No links, phone numbers or scammy words.** Lia refuses them with `bad_text` and a `problem` of `link`, `phone` or `scam`. The startParam is how you link into your app.
- **Make each one count.** Your app can send one person 3 a day (unless the Lia team changed it), an hour apart, and all apps together 6 a day. Spend them on things the person wants to know.
- **Write in their language.** Keep each player's `Lia.language` on your server when they open your app, and send in it.

## Testing

Testers get test notifications from your test key every 30 seconds and at least 20 a day, and they don't count toward their daily total from all apps. See [Testing](/guides/testing).