AWS Lambda - Basics

Basics Overview

At its core, basics is about doing one thing well inside your AWS Lambda project. Once you understand the pattern, you can apply it consistently across features and teams.

Good basics pays off across the whole codebase: fewer surprises, easier testing, and smoother onboarding. The snippet below is a solid starting point.

export const handler = async (event, context) => {
  console.log('event', JSON.stringify(event));

  return {
    statusCode: 200,
    headers: { 'content-type': 'application/json' },
    body: JSON.stringify({ message: 'Hello from Lambda' }),
  };
};

Every Node.js Lambda exports an async handler that receives the event and returns a response.

Basics Example

// handler.mjs
export const handler = async (event, context) => {
  // 1. read input from the event
  // 2. do the work
  // 3. return a response (or throw on error)
};

• Start from a minimal Basics example and grow it only as needed.
• Keep configuration explicit so Basics behaves the same in every environment.
• Name things clearly so teammates understand your Basics at a glance.
• Add tests around Basics early to lock in expected behaviour.

AWS Lambda Cheatsheet

Handy reference for working with basics in AWS Lambda and Node.js.

How Basics Works in AWS Lambda

Basics runs inside the managed Lambda execution environment. AWS provisions a micro-VM, loads your Node.js code, runs any module-scope initialisation once, and then invokes your handler for each event.

Every Node.js Lambda exports an async handler that receives the event and returns a response.

• Handlers should be small and do one job well.
• Initialise SDK clients and config outside the handler to reuse them on warm starts.
• Return quickly and let event sources handle retries where possible.
• Emit structured logs so CloudWatch and X-Ray can correlate activity.

Practical Guidance for Basics

On real projects, basics works best when it is observable, secure, and cheap to run. Grant least-privilege IAM, validate every input, and keep the deployment package small.

Common Mistakes

• Skipping error handling and edge cases when wiring up basics.
• Leaving basics untested, so regressions slip into production.
• Over-engineering basics before you actually need the extra flexibility.
• Ignoring documentation, which makes basics hard for the next developer to change.

Key Takeaways

• Basics is a core part of working effectively with AWS Lambda.
• Start small and keep basics focused on a single responsibility.
• Apply consistent patterns so basics scales across your project.
• Test and document basics to keep it maintainable over time.