Lambda — Complete Guide
Lambda — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of AWS Cloud Tutorial on Toolliyo Academy.
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AWS Cloud Tutorial · Lesson 26 of 100
Lambda
Core services → Projects
Core services · 1 — AWS basics · ~6 min · AWS — Compute Services
What is this?
AWS Lambda runs code without managing servers. You upload a handler; Lambda scales automatically and bills per millisecond of execution.
Why should you care?
AwsVerse uses Lambda for webhooks, PDF generation, and lightweight API backends with zero idle cost.
See it live — copy this example
Run in AWS CloudShell / local AWS CLI v2, or follow the matching steps in the AWS Console (Free Tier).
aws lambda create-function \
--function-name awsverse-webhook-handler \
--runtime nodejs20.x \
--role arn:aws:iam::123456789012:role/lambda-basic \
--handler index.handler \
--zip-file fileb://function.zip \
--timeout 30 --memory-size 256What happened?
- Deploys a Node.js function from a zip artifact.
- Attach IAM role with least privilege; trigger via API Gateway or EventBridge.
Practice next
- Write handler returning JSON status 200.
- Zip code; create function with lab role.
- Invoke with aws lambda invoke --function-name ... out.json.
- Add environment variable LOG_LEVEL=debug.
- Configure reserved concurrency of 10.
Remember
Lambda = event-driven compute. Pay per invocation and duration. Keep handlers small and stateless.
AwsVerse KYC webhook
Partner sends verification callbacks.
Outcome: Lambda validates signature and writes to DynamoDB in under 200 ms.
Interview prep for this lesson
Practice these questions aloud after reading—each links to a full structured answer.
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