Sidekiq
Simple, efficient background processing for Ruby
...It integrates seamlessly with Rails and other Ruby applications, letting developers offload tasks such as email delivery, file processing, and API calls so the main web process stays responsive. Sidekiq uses Redis as its backend, storing job queues, scheduling information, and retries, with support for delayed jobs and exponential backoff on failures. Its middleware architecture allows developers to inject custom logic around job execution, such as logging, tracing, or instrumentation. Sidekiq also provides monitoring dashboards for queue health, job latency, and failure analysis, giving teams operational visibility.