baileys_ex

# First Connection

You will finish this page with a live BaileysEx connection that can pair by QR code or phone pairing code.

## Before you begin

- BaileysEx compiles successfully in your project
- You chose an auth-state directory
- Your machine can reach `web.whatsapp.com`
- You have your phone nearby for pairing

## Steps

### 1. Load or create auth state

Load the saved auth state and the matching file-backed Signal store options before every connection attempt.

```elixir
alias BaileysEx.Auth.FilePersistence

auth_path = "tmp/baileys_auth"
{:ok, persisted_auth} = FilePersistence.use_multi_file_auth_state(auth_path)
```

If the directory is empty, `use_multi_file_auth_state/1` returns a fresh state for a new pairing flow and the `connect/2` options needed to persist Signal keys in the same directory.

### 2. Start the connection with a real transport

Use `BaileysEx.connect/2` with `BaileysEx.Connection.Transport.MintWebSocket`.

```elixir
alias BaileysEx.Connection.Transport.MintWebSocket

parent = self()

{:ok, connection} =
  BaileysEx.connect(
    persisted_auth.state,
    Keyword.merge(persisted_auth.connect_opts, [
      transport: {MintWebSocket, []},
      on_qr: fn qr -> IO.puts("Scan QR: #{qr}") end,
      on_connection: fn update -> send(parent, {:connection_update, update}) end
    ])
  )
```

The `:on_qr` callback gives you QR data for a new login. The `:on_connection` callback tells you when the socket opens or closes.

### 3. Persist updated credentials before pairing

Save credentials whenever the connection emits a `:creds_update` event.

```elixir
unsubscribe =
  BaileysEx.subscribe_raw(connection, fn events ->
    if Map.has_key?(events, :creds_update) do
      {:ok, latest_auth_state} = BaileysEx.auth_state(connection)
      :ok = persisted_auth.save_creds.(latest_auth_state)
    end
  end)
```

Attach this subscriber before you scan the QR or request a phone pairing code. Pair success emits the first credential update immediately.

### 4. Pair the session

For QR pairing, scan the QR from WhatsApp on your phone.

For phone pairing, request a code after the connection starts:

```elixir
{:ok, code} = BaileysEx.request_pairing_code(connection, "15551234567")
IO.puts("Enter this code in WhatsApp: #{code}")
```

Use only digits for the phone number. Do not include `+` or spaces.

## Check that it worked

Wait for a connection update like this:

```elixir
receive do
  {:connection_update, %{connection: :open}} -> :ok
end
```

You should also see new credential data written to your auth directory after pairing succeeds.

---

**Next steps:**
- [Send Your First Message](sending-your-first-message.md) — send a real text message through the paired connection
- [Authentication and Persistence](../guides/authentication-and-persistence.md) — wire auth saving and custom key storage cleanly