Backend
Background Jobs / Task Queues
Also written as Background Jobs, Task Queue, Celery, Sidekiq, BullMQ, Hangfire
Moving slow work (sending emails, generating reports, processing uploads) out of the web request into a queue that workers process separately, so users get a fast response. Celery (Python), Sidekiq (Ruby), BullMQ (Node) and Hangfire (.NET) are the usual tools.
Think of it like
A restaurant taking your order and giving you a buzzer, instead of making you stand at the counter while it's cooked.
Junior or senior?
Near-universal in real backends.
Senior sounds like
Talks about failed jobs, retries, jobs that run twice, and monitoring a backed-up queue.
Ask them
“What happened when a background job failed halfway through, or ran twice?”