What is AWS Serverless architecture?
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This question targets practical, hands-on experience with AWS / Cloud Computing. Interviewers want to see if you've worked with these concepts in real projects, not just read about them. Strong answers include concrete examples.
Answer
Serverless architecture on AWS means building applications without provisioning or managing servers — you focus on code, AWS manages infrastructure. You pay only when code runs, not for idle time. Core serverless services: Lambda (compute), API Gateway (HTTP frontend), DynamoDB (database), S3 (storage), EventBridge (event bus), SQS/SNS (messaging), Step Functions (orchestration), Cognito (auth), AppSync (GraphQL). Common serverless patterns: (1) Web API: API Gateway → Lambda → DynamoDB. Scales from 0 to millions with no changes; (2) File processing: S3 upload event → Lambda trigger → process (resize image, extract metadata, validate) → store result; (3) Event-driven: EventBridge rule → Lambda (e.g., new order event → send confirmation email, update inventory, notify warehouse); (4) Scheduled tasks: EventBridge cron → Lambda (generate reports, cleanup, sync data). AWS Step Functions: orchestrate multiple Lambda functions in a workflow. States: Task, Wait, Choice (branching), Parallel, Map (iterate), Pass. Handles retries, error handling, timeouts. Express vs Standard (different pricing/durability). SAM (Serverless Application Model): CloudFormation extension for serverless — simpler template syntax for Lambda, API Gateway, DynamoDB. sam local invoke for local testing. Benefits: no server management, automatic scaling, pay-per-use, built-in availability. Challenges: cold starts (Lambda), vendor lock-in, local development complexity, debugging distributed functions, 15-minute Lambda timeout limit.
Pro Tip
Back up your answer with a specific project or situation. Saying 'In my last AWS / Cloud Computing project, I used this when...' immediately makes your answer more credible and memorable.