AWS Lambda Explained for Beginners

Key Takeaways

That's where AWS Lambda comes in. AWS Lambda is a serverless compute service. Instead of launching and managing servers, you just write a function, a small piece of code, and AWS runs it for you. You don't worry about servers, operating systems, patching, scaling. You simply upload your code, define when it should run, and AWS handles the rest. They run only when triggered, and shut down automatically once they finish. This means you only pay for the exact time your code is running down to milliseconds. Lambda function can run when a file is uploaded to S3, an API is called, a database changes, a message arrives in a queue, or on a schedule. Lambda also scales automatically. If 10,000 events come in at the same time, AWS runs thousands of Lambda executions in parallel without you doing anything. And in our photo sharing app, Lambda is used as a background worker. Every time a user uploads a photo to S3, a Lambda function is triggered automatically to extract metadata from uploaded images without adding any load to our EC2 servers. It lets us run background tasks reliably at scale without managing any extra infrastructure.