When it comes to using Lambda, the use cases are literally unlimited. Anywhere there is a need to process some kind of information or process/transform/extract some kind of data, we can simply write a Lambda function to perform the task. The main business driver behind Lambda functions is that we never pay for any idling infrastructure and are able to match the cost of processing to the demand for services.

Lambda is also extremely cost-effective. When we start using Lambda, we get an indefinite free tier. The first million requests and 400,000 GB-seconds fall under the free tier; that is a lot of processing time that we essentially get for free. At the time of writing, the cost per request beyond the free tier is $0.0000002 and the cost per GB-second is $0.00001667. Putting that into perspective, if our website has 1 million visitors per day:

• Each visitor would represent one lambda invocation.
• Each response would take 100 ms to process the query from the user.
• Our lambda function would have 128 MB of memory assigned to it.
• The total cost for this application would be under $10 per month.