# Invites and links

> Bring friends into your app with Lia's friend picker, or a link anyone can open. Both open your app with a startParam, so friends land in the same match or room. From the Lia developer docs: https://docs.lialabs.org/concepts/invites

## Two ways in

| | `Lia.inviteFriend()` | `Lia.inviteLink()` |
| --- | --- | --- |
| What it is | Lia's friend picker | A link to your app |
| Reaches | The person's Lia friends, as a card in their Lia chat | Anyone you share it with, anywhere |
| Opens | Your app in Lia, with your `startParam` | Your app in Lia, with your `startParam`, or the App Store without Lia |
| Answers | `{ invited }`: whether anyone was invited | The link, straight away |

## The startParam

A startParam is how an invite says where to go: your match, room, table or anything else. It's 1 to 64 characters of letters, digits, `_` and `-`. When someone opens your app from an invite, a link or a [notification](/concepts/notifications), `Lia.startParam` holds it. If your app is already open, your page hears a `startParam` event instead.

```js
// Make a room on your server, then invite into it.
const room = await createRoom(); // "room-k3x9"
await Lia.inviteFriend({ startParam: room });

// Whoever opens the invite lands in the same room.
Lia.init().then(function () {
  if (Lia.startParam) joinRoom(Lia.startParam);
  Lia.ready();
});
Lia.on("startParam", function (data) { if (data.startParam) joinRoom(data.startParam); });
```

Treat a startParam as a hint from anyone: check on your server that the room exists and the player may join it.

## The friend picker

`Lia.inviteFriend()` opens Lia's own sheet over your app, with the person's friends and a way to share the link elsewhere. Each friend they pick gets a card in their Lia chat that opens your app. Your app only hears whether anyone was invited (or the link was shared), never who.

Lia keeps it friendly:

- **Friends only.** People can only invite their Lia friends, and not anyone either of them has blocked.
- **Who can open it.** While your app is in test, only your testers can be invited.
- **20 a day.** One person can invite at most 20 friends into your app a day.

## Invite links

`Lia.inviteLink(startParam)` gives you a link like:

```text
https://api.lialabs.org/play/your-app?start=room-k3x9
```

Opened on a phone with Lia, it opens your app with the startParam. Without Lia, it shows a page in the phone's language with a way to get Lia. Call it after `Lia.init()`; without a startParam it's a link to your app itself.

```js
const link = Lia.inviteLink(room);
await Lia.share("Play with me: " + link);
// or
await Lia.copyText(link);
```

[Multiplayer with invites](/guides/multiplayer-with-invites) builds a two player room from start to finish.