In modern web applications, keeping the Request-Response cycle fast is crucial for user experience. If a user registers on your Rails 8 app and you trigger a welcome email directly inside the controller, the browser will remain in a loading state until the SMTP server responds.
To solve this, we offload heavy, non-blocking tasks (like sending emails, generating PDFs, or syncing third-party APIs) to background workers. While Rails 8 now introduces Solid Queue as its default database-backed adapter, Sidekiq remains the industry gold standard for high-throughput, multi-threaded asynchronous processing powered by Redis (an in-memory data store).
1. System Requirements & Installation
