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