Sidekiq Setup Basics

Direct Answer

To run Sidekiq with Rails, add the sidekiq gem, provide a supported Redis-compatible server and URL, configure the queues and worker concurrency, and start a Sidekiq server process separately from the Rails web process. Native jobs include Sidekiq::Job; Active Job applications set config.active_job.queue_adapter = :sidekiq. The producer and worker must share compatible code, queue names, and serialization expectations. Production setup also needs authentication for the Web UI, graceful shutdown, error reporting, and queue health monitoring.

Deep Dive & Architecture

The web process only needs client configuration to enqueue, while the Sidekiq server boots the Rails application to execute job code. A deployment can therefore have healthy web instances and no functioning workers. Process supervision and health checks must treat them as separate services.

Queue configuration is routing. The payload names a queue, and a worker process declares which queues it polls. Strict priority can starve low-priority work when high-priority traffic never clears; weighted or specialised processes trade strict ordering for capacity isolation. Fewer purposeful queues are easier to operate than one per feature.

Sidekiq concurrency is threaded within each process. Every blocking job may hold a database connection or network socket. Pool sizes, client timeouts, thread safety, and downstream quotas must be coordinated with total concurrency across all worker processes, not tuned from a single machine in isolation.

The Web interface exposes operational state and can retry or delete work, so mounting it without authentication creates an administrative vulnerability. Logs and metrics should identify job class, queue, runtime, retry count, and a safe business correlation key without placing secrets in job arguments.

Code Example

# config/application.rb
class Application < Rails::Application
  config.active_job.queue_adapter = :sidekiq
end

# config/sidekiq.yml
# :concurrency: 5
# :queues:
#   - critical
#   - default
#   - mailers

# Start separately from the Rails web server:
# bundle exec sidekiq -C config/sidekiq.yml

Common Mistakes & Pitfalls

Exposing the Sidekiq Web UI without auth in production (anyone could retry/kill jobs).