Example of using a GenServer for recurring background work

recurring_genserver.ex

defmodule CryptoApp.AccountSync do
  use GenServer

  @interval 1_000

  def start_link do
    GenServer.start_link(__MODULE__, :ok, name: __MODULE__)
  end

  def init(:ok) do
    Process.send_after(self(), :work, @interval)
    {:ok, %{last_run_at: nil}}
  end

  def handle_info(:work, state) do
    fetch_account_balance()
    Process.send_after(self(), :work, @interval)

    # by storing last_run_at in state we get basic monitoring via process inspection
    # it's just for convenience - don't use this technique for sophisticated instrumentation
    {:noreply, %{last_run_at: :calendar.local_time()}}
  end

  defp fetch_account_balance do
    # your code here
  end
end