AWS for Backend Developers (EC2, S3, RDS, Lambda) · Lesson

Monitoring and Debugging Lambda Functions

Learn how to observe, log, trace, and troubleshoot AWS Lambda functions in production using CloudWatch, X-Ray, and structured logging.

Why Observability Matters

Serverless functions are short-lived and invisible — you cannot SSH into them. Observability is how you understand what your Lambda is doing.

The three pillars are logs, metrics, and traces.

Anything your function writes to stdout/stderr goes to CloudWatch Logs automatically. Each function gets its own log group.

exports.handler = async (event) => {
  console.log('Received event:', JSON.stringify(event));
  return { statusCode: 200, body: 'OK' };
};