What are some alternatives?
Faktory - a station where factors reside and trade; a building or set of buildings with facilities for manufacturing; the seat of some kind of production… See the full definition
Sidekiq - Sidekiq is a simple, efficient framework for background job processing in Ruby
RabbitMQ - RabbitMQ is an open source message broker software.
Beanstalkd - Beanstalk is a simple, fast work queue.
IBM MQ - IBM MQ is messaging middleware that simplifies and accelerates the integration of diverse applications and data across multiple platforms.
delayed_job - Database based asynchronous priority queue system -- Extracted from Shopify - collectiveidea/delayed_job