Celery

 Celery  is a Python-based tool for executing asynchronous background tasks, distributing tasks amongst many worker processes, and running scheduled or period tasks (via Celerybeat). It can be backed by Redis or RabbitMQ (officially; other transports are experimental) for messaging passing and persistence.

IndieWeb Examples

 * Woodwind uses Celery backed by Redis for periodic feed polling, and for background processing like updating a feed in response to a PuSH ping.