AWS Services
What Is AWS Lambda? A Beginner's Guide to Serverless
Learn the basics of AWS Lambda, its benefits and limitations, and how it works with API Gateway and DynamoDB, explained for beginners.
AWS Lambda is a service that lets you run code without managing servers. It is one of the core services to learn when you study serverless architectures.
Summary
Lambda is a compute service that runs functions in response to events. It only runs when needed, which makes it a good fit for low-traffic personal MVPs.
What Does Serverless Mean?
Serverless does not mean there are no servers. It means AWS manages the servers for you, so developers can focus on code and configuration.
You do not need to manage an OS like you do with EC2, or run an always-on server.
When to Use Lambda
Lambda is used for API processing, image conversion, scheduled batch jobs, event processing, and integration with services like DynamoDB.
On this site, we use Lambda to receive contact form submissions, validate the input, and save it to DynamoDB.
Combining Lambda with API Gateway
Lambda alone cannot serve as the entry point for a web API. You use API Gateway to accept HTTP requests, and API Gateway invokes Lambda.
A typical setup is: the frontend calls POST /contact, API Gateway invokes Lambda, and Lambda saves the data to DynamoDB.
Things to Keep in Mind
Lambda has limits on execution time, memory, and concurrency. Cold starts can also happen.
For a personal MVP, keep your function short, reduce external dependencies, and avoid writing personal information to logs.
Key Points for the Exam
- Lambda is serverless compute
- It runs based on events (event-driven)
- You can build APIs by combining it with API Gateway
- It integrates easily with AWS services like DynamoDB
- You do not manage always-on servers
Related Terms
What to Read Next
What to learn next
Combine blog posts with the AWS glossary, service comparisons, practice questions, and architecture gallery to connect exam knowledge with implementation.