Open-source Ruby background job processor backed by Redis, with paid Pro and Enterprise editions. Simple to get started with, scales from a few jobs to millions, and works outside Rails. Pro/Enterprise add features such as batches, rate limiting and extra patches, distributed as paid gems via a private RubyGems server. As of Sidekiq 6 log redirection must be configured by the application. Sidekiq 7 drops the 'worker' terminology in favor of 'job', turns complex-argument warnings into hard errors (pushing invalid jobs to the dead queue), removes the delayed extension (to live on as a separate gem), and introduces a fix for the long-standing problem of jobs enqueued inside a transaction running before the transaction commits.