What are queues and background jobs?

A queue lets your app hand slow work to background workers instead of making users wait:

• Examples: sending emails, generating PDFs and payslips, importing spreadsheets, resizing images, syncing with other systems
• Tools: AWS SQS, RabbitMQ, BullMQ (Redis), or scheduled cron jobs for nightly work

Why: pages stay fast, work survives restarts (it's retried), and you can add workers when volume grows.