Phoenix LiveView provides four async functions that leverage Elixir's lightweight processes for asynchronous work: (1) assign_async/4 for simple data fetching that automatically updates assigned values, (2) stream_async/4 for initial page loads with collection data integrated with Phoenix Streams, (3) start_async/4 and handle_async/3 for complex workflows with full control and cancellation support. Each async operation is managed through Phoenix.LiveView.AsyncResult which tracks status (loading, ok, failed). For streaming scenarios like LLM-style output, use start_async/4 with message passing: spawn a process that sends incremental updates via send(pid, {:message, data}), then handle these messages in handle_info/2 to update the UI in real-time. Example: socket |> start_async(:data_stream, fn -> stream_response(pid) end) where the spawned process sends data chunks that are received and rendered progressively.