What is AWS Lambda?
Answer
AWS Lambda is Amazon's serverless compute service and the most widely used FaaS platform. It runs code in response to events and automatically manages the underlying compute resources. Key characteristics: (1) Supported runtimes — Node.js, Python, Java, Go, Ruby, C#/.NET, and custom runtimes via Lambda Layers; (2) Triggers — API Gateway, S3, DynamoDB Streams, SQS, SNS, EventBridge, Cognito, and 200+ other services; (3) Execution limits — up to 15 minutes, 10GB memory, 512MB ephemeral disk (/tmp), 6MB payload limit; (4) Concurrency — up to 1000 concurrent executions by default (soft limit, can be raised); (5) Billing — charged per 1ms of execution time and per million requests. Lambda functions are stateless — any state must be stored in external services (DynamoDB, S3, ElastiCache).