AWS Lambda

AWS Lambda is a serverless compute service that runs code in response to events without provisioning or managing servers. You pay only for the compute time consumed - there's no charge when code isn't running.

Key Features

Event-driven: Triggered by AWS services, HTTP requests, or schedules
Auto-scaling: Scales from zero to thousands of concurrent executions
Pay-per-use: Billed per 1ms of execution time
Multiple runtimes: Node.js, Python, Java, Go, .NET, Ruby, and custom runtimes

Common Triggers

Trigger	Use Case
API Gateway	REST/HTTP APIs
S3	File processing
DynamoDB Streams	Database change events
SQS	Message processing
EventBridge	Scheduled tasks, event routing
Cognito	Authentication triggers

Function Configuration

// handler.js
exports.handler = async (event) => {
  const name = event.queryStringParameters?.name || 'World';
  return {
    statusCode: 200,
    body: JSON.stringify({ message: `Hello, ${name}!` }),
  };
};

Limits and Quotas

Resource	Limit
Timeout	15 minutes
Memory	128 MB - 10 GB
Deployment package	50 MB (zipped), 250 MB (unzipped)
Concurrent executions	1,000 (soft limit)
`/tmp` storage	512 MB - 10 GB

What We Like

Zero infrastructure: No servers to manage, patch, or scale
Cost efficient: Only pay for actual execution time
Fast deployment: Push code and it's live
Tight AWS integration: First-class support throughout AWS

What We Don't Like

Cold starts: First invocation after idle can be slow
Stateless: No persistent connections or in-memory state
Debugging: Local development doesn't perfectly match production
Vendor lock-in: Lambda-specific patterns can be hard to migrate

Cold Start Mitigation

Use Provisioned Concurrency for latency-sensitive workloads
Keep functions warm with scheduled pings
Choose runtimes wisely (Node.js and Python start faster than Java)
Minimise deployment package size

Key Features​

Common Triggers​

Function Configuration​

Limits and Quotas​

What We Like​

What We Don't Like​

Cold Start Mitigation​