A way to tell a person, besides the feed and email: Telegram, SMS, Slack, Discord, the app's own push. The app writes a module and names it in the config's :channels:

{Chime, ..., channels: [telegram: {MyApp.Chime.Telegram, token: "..."}]}

defmodule MyApp.Chime.Telegram do
  @behaviour Chime.Channel

  @impl true
  def deliver(%Chime.Message{} = message, opts) do
    case message.recipient.data do
      %{telegram_chat: nil} ->
        {:skip, "the person has no Telegram chat"}

      %{telegram_chat: chat} ->
        %{title: title} = Chime.Message.render(message)

        case Telegram.send(opts[:token], chat, title) do
          {:ok, %{"message_id" => id}} -> {:ok, to_string(id)}
          {:error, :blocked} -> {:skip, "the person blocked the bot"}
          {:error, reason} -> {:error, reason}
        end
    end
  end
end

and a notifier delivers by it: deliver :telegram.

deliver/2 gets the Chime.Message (the notification, the person, the notifier's data) and the options of the config, and answers:

• {:ok, ref} or :ok - sent; ref, a string, is kept (the service's id of it);
• {:skip, reason} - not sent, on purpose, and not tried again: the reason goes in the log (Chime.Explain);
• {:error, reason} - failed: Oban tries again, with its backoff, and the delivery is "failed" after the last attempt.

Whether it goes at all (the person's preferences, :if, :unless) is decided before deliver/2 is called.