Each outgoing bubble shows a status: queued (accepted, awaiting carrier confirmation), sent (single check), delivered (double check), failed or undelivered (red check; hover for the status). Messages that are still waiting for the sending job show "Sending on: <time>" and, if a previous attempt errored, the error text on hover. In the current version, statuses are updated only when Twilio calls back your site's delivery-status webhook after each send — there is no separate background job that re-checks message status in production (a poll-and-refetch step exists in the code but only runs in the development environment).