AWS Lambda

What This Service Solves

Lambda runs code in response to events without managing servers. Your code must fit the runtime, timeout, event, and concurrency model.

• Use Lambda for event handlers, APIs, stream processors, scheduled jobs, glue code, and bursty workloads.

When You Should Not Use It

• Avoid Lambda for long-running jobs beyond service limits, workloads needing persistent local state, or specialized host control.

What AWS Manages and What You Manage

AWS manages runtime infrastructure. You manage code, dependencies, handler behavior, permissions, memory, timeout, concurrency, and event-source settings.

Security Implications

Execution role scope, environment variable protection, KMS, VPC access, dependency security, and log handling matter.

Availability and Scaling

Lambda runs across multiple AZs in a Region by design, but downstream services and concurrency limits can still fail the workload.

Lambda scales with events until concurrency limits or downstream bottlenecks appear. Reserved concurrency can protect or throttle workloads.

Cost Behavior

Pay by requests and duration. Memory setting changes CPU and cost. Idle cost is near zero, but retries can multiply cost.

Common Integrations

• API Gateway
• EventBridge
• SQS
• SNS
• DynamoDB Streams
• CloudWatch Logs

How AWS Might Present It

Certification-Specific Depth

Related Comparisons

Sources and Review Metadata

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