# `WhatsApp.WebhookPlug.Handler`
[🔗](https://github.com/jeffhuen/whatsapp_sdk/blob/main/lib/whatsapp/webhook_plug/handler.ex#L1)

Behaviour for WhatsApp webhook event handlers.

Implement this behaviour to process incoming webhook events from the
WhatsApp Business API. Each event corresponds to a `"value"` entry
from the webhook payload's `"changes"` list.

## Example

    defmodule MyApp.WhatsAppHandler do
      @behaviour WhatsApp.WebhookPlug.Handler

      @impl true
      def handle_event(%{"messages" => messages} = _event) do
        Enum.each(messages, &process_message/1)
        :ok
      end

      def handle_event(_event), do: :ok

      defp process_message(message) do
        # Handle the message
        IO.inspect(message, label: "Received WhatsApp message")
      end
    end

# `handle_event`

```elixir
@callback handle_event(event :: map()) :: :ok | {:error, term()}
```

Called for each webhook event received from the WhatsApp Business API.

The `event` map is the `"value"` from each change entry in the webhook
payload. It typically contains keys like `"messages"`, `"statuses"`,
`"contacts"`, `"metadata"`, etc.

Return `:ok` on success or `{:error, reason}` on failure. Note that
returning an error does not change the HTTP response sent to Meta
(which is always 200 to acknowledge receipt).

---

*Consult [api-reference.md](api-reference.md) for complete listing*