====== Lambda ======

**What it is:** A serverless compute service that runs your code in response to events.

**What it’s for:**
  * Event-driven processing (S3 upload → process file).
  * APIs (with API Gateway).
  * Automation and glue logic between services.

**Key ideas:**
  * You deploy a function; AWS runs it when an event occurs.
  * Pricing is based on requests and execution time.
  * Scaling is automatic (with concurrency limits).

**Exam cues:**
  * “run code without servers” → Lambda.
  * “trigger code when an object is uploaded to S3” → Lambda trigger.

**Hard words:**
  * *serverless* /ˈsɝːvərləs/: không quản server
  * *event-driven* /ɪˈvent ˈdrɪvn/: hướng sự kiện
  * *execution* /ˌeksɪˈkjuːʃn/: thực thi