A background service that processes tasks asynchronously, usually taken from a queue or stream.

• Async Processing (Fast)
• Scalable (can scale workers)
• Fault tolerance (worker crashed, another worker pickup and continue)
• Load Smoothing (Queue absorbs tasks)

❌ Without Worker

Slow, timeout, Not scalable

1. User uploads image
2. API processes image
3. AI runs
4. store result
5. return response

✅ With Worker:

Fast API, Scalable, Reliable

1. User uploads
2. API saves task
3. Stored into queue
4. Simultaneously:
   1. API return immediately
   2. Worker picks task → process → store result