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ruby erb 24 lines · 3 tabs

Action Mailbox: broadcast incoming emails into a feed

Henry Kim Jan 2026
3 tabs 
class SupportMailbox < ApplicationMailbox
  def process
    ticket = Ticket.find_or_create_by!(message_id: mail.message_id) do |t|
      t.subject = mail.subject
      t.from_email = mail.from&.first
      t.body = mail.decoded
      t.account = Account.find_by!(inbound_address: mail.to&.first)
    end

    ticket.broadcast_prepend_later_to(
      [ticket.account, :tickets],
      target: 'ticket_feed'
    )
  end
end
3 files · ruby, erb Explain with highlit

For apps that ingest emails (support inbox, replies), Action Mailbox is a natural fit. When a message arrives, I create a record and broadcast it into a Turbo Stream feed so the UI updates in realtime. This is essentially “email as an event source”. The mailbox extracts metadata (from, subject, body), persists it, and then broadcasts a prepend to the appropriate stream (scoped to the account/team). The UI subscribes with turbo_stream_from and renders the message partial. The benefit is that operators can watch incoming mail live without polling. The key considerations are deduplication (Message-ID), security (only authorized users subscribe), and sanitization (render email body safely). Hotwire keeps it simple: rendered partials, no bespoke websocket protocol.

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