Completely opposite to the cold start, where a new instance of the function needs to be created and brought up to the execution, the hot start of the function utilizes the existing instance of the function that is already running in the infrastructure of the provider. When this happens, an incoming request does not have to spend time waiting for a new instance to spawn up before the request can be handled. This allows for the request to be processed quickly.

There is one thing that needs to be noted here: even in the case of a hot start of a function, the state from the previous execution of the function is not stored.

Now we know about one of the major factors on which the performance of a function may depend. Let's now move forward and build our first serverless application.