AWS Lambda: Full Guide with Features, Benefits, and Pros and Cons

AWS Amazon Web Services

AWS Lambda: Full Guide with Features, Benefits, and Pros and Cons

Are you tired of managing servers and constantly worrying about infrastructure? Do you wish you could just focus on writing code and let someone else handle the heavy lifting? Let me introduce AWS Lambda. Lambda’s claim of serverless computing seems too good to be true at first. If you think about it, there must be a server somewhere. If you host a web application or a website, there is always a server on the backend, keeping things running.

Developed by the wizards at Amazon Web Services, Lambda lets you run your code without managing any servers. That’s right, no more late-night server maintenance or panicked calls to IT support.

You can actually write and run your code in response to various events, such as a new message in an SQS queue or a change to data in an S3 bucket. All the while, AWS automatically scales your application and runs your code in response to these events without any need for manual intervention. So you only pay for the computing time you use rather than wasting money on idle servers.

So, if you don’t have to manage servers, and you don’t have to pay for idle server time, what is the catch? What makes Lamdba so great, and is there anything you should beware of when learning about this fascinating service? Let’s get into the facts!

Must-Know Facts About AWS Lambda

  • AWS Lambda is event-driven, meaning it only runs when triggered by an event, such as changes to data in Amazon S3 or a new message in an Amazon Kinesis stream.
  • AWS Lambda supports multiple programming languages, including Node.js, Python, Java, Go, and more.
  • AWS Lambda is highly scalable, automatically running multiple instances of your function in parallel to handle increases in traffic.
  • AWS Lambda integrates seamlessly with a variety of other AWS services, including Amazon S3, DynamoDB, and Kinesis.
  • AWS Lambda has a pricing model based on the number of requests and the amount of compute time used. This can be cost-effective for applications with infrequent or unpredictable usage patterns.

What is AWS Lambda: Explained

Just two decades ago, the internet was a vastly different place for your typical business. If you had an app or a web service that you wanted to offer to the general public, you needed to set up your own infrastructure, with servers, networking gear, and the hassle of configuring your own software. Maintaining all of this hardware usually meant hiring an expensive in-house IT department to manage it all.

Amazon stepped on the scene in 2006 with EC2 or “Elastic Compute Cloud.” It was a revolutionary idea at the time. Instead of dealing with server maintenance and paying for a bunch of hardware, you could just order compute capacity and rent virtual servers for an allotted amount of time from AWS.

Cloud services exploded in popularity overnight, and while this was a paradigm shift compared to the old method, Amazon had something up their sleeve to make it even better. You see, with EC2, you still needed to pay for your allotted time with the hardware, so it could get expensive, even if you weren’t actively executing any code or actions on your server.

Enter AWS Lambda

When AWS Lambda launched in 2014, it introduced the pay-per-execution model. In other words, you don’t pay for the physical hardware, you just pay for how many times you want to run your code.

With Lambda, you can write your code in your language of choice (Python, Java, or Node.js) and upload it to the service. Then, you can trigger your code to run in response to a variety of events, such as updates to a DynamoDB table, changes to data in an Amazon S3 bucket, or an HTTP request through Amazon API Gateway. The best part? You don’t have to worry about provisioning servers, configuring databases, or dealing with any other headaches that come with managing infrastructure.

Instead, Lambda automatically scales your application and runs your code in response to events without any need for manual intervention. This means that you only pay for the cloud computing time you use rather than paying for idle servers. Plus, AWS Lambda supports integrations with other AWS services, so you can easily build powerful, event-driven applications.

So how does Lambda work? What makes everything function? Well, keep reading to learn exactly that!

Largest data center companies
AWS Lambda supports integrations with other AWS services.

©Gil C/Shutterstock.com


This is where the magic happens! Lambda functions are the powerhouses that run your code in response to an event. Plus the best part? You can write functions in a variety of programming languages, including popular choices like Node.js, Python, Java, and Go.

Functions are, basically, just blocks of code. You can have a function that hosts a REST API or a function that performs nightly backups. Anything under the sun. Generally speaking, they are the backbone of your Lambda workflow.

Event Sources

For your function to work, you need something to trigger it. That’s exactly what an event source is: an action that triggers your function. Lambda supports a wide range of event sources, including popular AWS services like Amazon S3, DynamoDB, and Kinesis. That’s not all — you can also use services like SNS and SES for setting up a highly automated communications infrastructure.

One example of an event source in action is a text message or an email. You could set up SNS to trigger a text message to a customer when a business sends an email. Or adding data to a database upon receiving a text message. You can really use your imagination for event sources.


Lambda is so attractive compared to using a service like EC2 because of auto-scaling. In other words, Lambda can automatically scale to support extremely high levels of throughput. Compared to manually scaling your computing resources, auto-scaling tries to let you focus more on the functionality as opposed to worrying about the minutia of scaling your servers

Runtime Environment 

Since it’s a “Serverless” environment, you don’t have to worry about security as much. Setting up a firewall or configuring security systems used to take up a lot of time, especially in the days before EC2. Lambda makes it even easier, using Amazon’s built-in security mechanisms.

Monitoring and Logging

AWS Lambda provides comprehensive monitoring and logging capabilities, including metrics, logs, and tracing, which help you troubleshoot and optimize your functions.

These components and features of Lambda provide a flexible and robust platform for building and running applications. Whether you’re developing a small microservice or a large-scale application, AWS has got you covered with its powerful and reliable infrastructure.

How to Use AWS Lambda

If you want to use Lambda, you need to have a few basic ingredients in order. First, you need an AWS account. The good news is that Lambda is available on the free tier, and you get a pretty generous allotment each month. 

You’ll need to have a foundational knowledge of AWS, so studying for an exam like the AWS Certified Cloud Practitioner might be a good investment. However, you don’t need to pay for the knowledge. You can often find help on YouTube or other online resources, with tutorials specific to your use case.

The meat and potatoes of what you’ll be doing is creating functions and configuring event sources. Creating a Lambda function is easy — just head to the AWS Management Console or use the AWS CLI. 

Amazon Web Services
To begin using Lambda, you will need to have a foundational knowledge of AWS.


How to Learn AWS Lambda

If you don’t know anything about AWS, looking into a service like Lambda can be intimidating. However, if you want to understand it and build something with it for your own apps, the good news is that it is not as confusing as it looks. If you’re eager to learn Lambda, there are plenty of resources available to help you get started. Here are some tips to help you dive into this exciting service:

Begin with the Official Documentation

The AWS documentation doesn’t look flashy and might be a little boring, but it is, without a doubt, the most factual resource on the topic you’ll find. However, reading the documentation to learn is like reading the dictionary to learn a language. It’s just not the right way to go about it.

Instead, combine the documentation with tutorials and your own projects. Consult the docs when you run into a bug or a roadblock that you can’t figure out. 

Take Advantage of Online Tutorials and Courses

A ton of websites with paid and free tutorials and courses already exist, especially since Lambda has been around since 2014. These courses cover various topics, such as serverless architectures, event-driven programming, and serverless deployment, and can help you get up to speed quickly. 

AWS Lambda: When is it Not The Best Choice?

AWS Lambda is not the only player in the serverless computing game. Just to name a few, you have Google App Engine, Azure Functions, and even Heroku. All of these services offer their own unique approach, and they all have their drawbacks. For applications that require more flexibility and control over their environment, containerization technologies like Docker and container orchestration platforms like Kubernetes may be a better fit. While these options require more setup and management than serverless compute services, they provide more flexibility and control over your environment.

While we won’t get into an AWS vs. Azure, or an AWS vs. Heroku battle here, we can think of a few good situations where Lambda might NOT be the best service to pick. Often another Amazon service is the answer.

If You Need Long-Running Tasks

A long-running or continuous code execution might be a little too heavy for Lambda. Since Lambda functions have a maximum runtime of 15 minutes, they may not be the best choice for this kind of work. In this case, Amazon EC2 or AWS Batch are more appropriate alternatives.

If Your App Has High Memory Requirements 

Lambda functions have a memory limit that ranges from 128 MB to 10 GB–probably not enough for apps with excessive memory requirements. AWS Elastic Container Service, better known as simply ECS, or EC2 are both better choices for these applications.

If Your App Requires Persistent Storage 

If you need persistent storage, or more simply put, you need your app to remember something when the user logs off, a Lambda function is not the best answer. They are stateless by design and do NOT provide persistent storage. If your app has to have it, both Amazon Elastic File System and Amazon Elastic Block Store offer persistent storage.

If Cost-Per-Request Does Not Fit Your Budget

AWS charges you based on the number of requests and execution time, which can add up quickly for high-traffic applications. In some cases, running your own servers on EC2 or using ECS may be more cost-effective.

If You’re Just Hosting a Simple Website

Lambda is not the ideal choice if your needs are simple. Most plain old business websites — the ones that don’t have a lot of functionality or a huge user base — won’t have any use for services like Lambda. If you have a static website or you want to launch a WordPress site, you’re much better off with hosting providers like Siteground, Bluehost, or WPengine.

Siteground web hosting website
SiteGround may be a better option for users with a static website or a WordPress site.

©Postmodern Studio/Shutterstock.com

AWS Lambda: Release History

Since its launch in 2014, Lambda has undergone several updates and improvements that have made it a leading serverless compute service. One of the notable releases in 2018 was the support for custom runtime, allowing developers to use any programming language to write Lambda functions. This feature greatly expanded the options available to developers and enabled them to work in their preferred programming language.

AWS announced Lambda Layers in 2019. This was actually a pretty major update, because it finally allowed developers to share code and dependencies across multiple functions, saving a lot of time and resources.

The last few years have been nothing short of impressive for Lambda. Constant updates see support for a new language or event source almost every week. New capabilities like error handling and asynchronous invocation might sound like buzzwords, but they add a lot of functionality to the service in the form of a more robust and efficient platform.

Frequently Asked Questions

What is AWS Lambda used for?

Simple things, like placing an item in your online shopping cart, or anywhere you want an event to trigger a function.

What are the 3 components of AWS Lambda?

The function, or code that performs the task, the configuration, which is what determines the specifics of how your function is executed, and finally the event source, which is what triggers your function.

What is equivalent to AWS Lambda?

Azure Functions is a highly competitive alternative with a very similar function and trigger system.


Which language is best for AWS Lambda?

Python is widely regarded as the best language for writing Lambda functions to its speed.

Should I use AWS Lambda to host my website?

Lambda is not the best choice for most websites. In fact, many WordPress hosting services or other existing platforms are more suited for most sites. Lambda shines when you need to host an application that requires event-driven functions.

To top