Lambda is relatively simple and straightforward. You basically write a function/script (in a language like PHP, Python, Node.js, etc.) and then you can associate a trigger that will invoke that function on-demand whenever you need it to run. The trigger could be an HTTP endpoint for example. So you could have your web domain associated with a lambda function which generates and responds with the HTML content for the webpage that was requested. Lambda uses a "serverless" design where you don't have to worry about managing servers or scaling instances. Instead it's a simple pay per use model where you can trigger and execute your function/script on demand and just pay for what you use. One disadvantage of using Lambda (as opposed to an always-running compute service like EC2) is that you may experience slow 'cold start' times when a function hasn't been executed in a long time or suddenly there are multiple execution requests that happen concurrently. This sometimes causes a delay of a couple of seconds (or in some cases even longer). Another disadvantage is that you can't use Lambda for continuous/long-running processes. It's designed for a request-response model where you send a request to the Lambda function and wait for a response and the maximum execution time is a few minutes. If this is acceptable to you, then Lambda is a very powerful tool and is an easy way to get started with cloud computing without having to worry about managing servers. Answer from pythonpoole on reddit.com